CVE-2023-4911: Glibc: buffer overflow in ld.so leading to privilege escalation
Noroxi assessment
Priority: Now (action score 80/100)
- CISA has confirmed exploitation in the wild (Nov 21, 2023). Remediation deadline for US federal agencies: Dec 12, 2023.
- A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
- Probability of exploitation in the next 30 days: 63.7% (FIRST EPSS); higher than 99.2% of all records.
- Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: Azure Linux 3.0 ARM 2.38-6; Azure Linux 3.0 x64 2.38-6; CBL Mariner 2.0 ARM 2.35-5.
Patch today or shut off access. Upgrade to Azure Linux 3.0 ARM 2.38-6; Azure Linux 3.0 x64 2.38-6; CBL Mariner 2.0 ARM 2.35-5 or later.
Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it
Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS
A buffer overflow was discovered in the GNU C Library's dynamic loader ld.so while processing the GLIBC_TUNABLES environment variable. This issue could allow a local attacker to use maliciously crafted GLIBC_TUNABLES environment variables when launching binaries with SUID permission to execute code with elevated privileges.
- Published
- Oct 3, 2023
- Updated
- Oct 14, 2026
- EPSS
- 63.7% · 99th percentile
- CWE
- CWE-122
Report tools
Action score
80
Now
Patch today or shut off access.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 19 / 30 · 63.7%
CISA SSVC decision
- Exploitation
- active
- Automatable
- no
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.8
- CNA · redhat
- 7.8
- agree
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Nov 21, 2023. That signals real attacks, not theory.
Remediation deadline for US federal agencies: Dec 12, 2023.
Get told when this record changes
- In CISA KEV: exploitation in the wild confirmed
- Weaponized exploit exists
- A fix has been released
If any of these changes, we'll tell you in the daily email digest.
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Noroxi analysis
What does it mean in your environment?
The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.
We use this product, ask for helpAffected systems
Is your version affected?
Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.
| Vendor | Product | CPE |
|---|---|---|
| gnu | glibc | cpe:2.3:a:gnu:glibc |
| netapp | bootstrap os | cpe:2.3:o:netapp:bootstrap_os |
| netapp | hci compute node | cpe:2.3:h:netapp:hci_compute_node |
| siemens | simatic s7-1500 cpu 1518-4 pn/dp mfp firmware | cpe:2.3:o:siemens:simatic_s7-1500_cpu_1518-4_pn/dp_mfp_firmware |
| siemens | simatic s7-1500 cpu 1518-4 pn/dp mfp | cpe:2.3:h:siemens:simatic_s7-1500_cpu_1518-4_pn/dp_mfp |
| siemens | simatic s7-1500 cpu 1518f-4 pn/dp mfp firmware | cpe:2.3:o:siemens:simatic_s7-1500_cpu_1518f-4_pn/dp_mfp_firmware |
| siemens | simatic s7-1500 cpu 1518f-4 pn/dp mfp | cpe:2.3:h:siemens:simatic_s7-1500_cpu_1518f-4_pn/dp_mfp |
| siemens | siplus s7-1500 cpu 1518-4 pn/dp mfp firmware | cpe:2.3:o:siemens:siplus_s7-1500_cpu_1518-4_pn/dp_mfp_firmware |
| siemens | siplus s7-1500 cpu 1518-4 pn/dp mfp | cpe:2.3:h:siemens:siplus_s7-1500_cpu_1518-4_pn/dp_mfp |
| siemens | simatic s7-1500 tm mfp firmware | cpe:2.3:o:siemens:simatic_s7-1500_tm_mfp_firmware |
| siemens | simatic s7-1500 tm mfp | cpe:2.3:h:siemens:simatic_s7-1500_tm_mfp |
| fedoraproject | fedora | cpe:2.3:o:fedoraproject:fedora |
and 37 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux22.04
- canonical ubuntu linux23.04
- debian debian linux11.0
- debian debian linux12.0
- fedoraproject fedora37
- fedoraproject fedora38
- fedoraproject fedora39
- gnu glibc2.34 and later · before 2.39
- netapp bootstrap osall versions
- netapp h300s firmwareall versions
- netapp h410c firmwareall versions
- netapp h410s firmwareall versions
- netapp h500s firmwareall versions
- netapp h700s firmwareall versions
- netapp ontap select deploy administration utilityall versions
- redhat codeready linux builder9.0
- redhat codeready linux builder eus8.6
- redhat codeready linux builder eus9.2
- redhat codeready linux builder eus9.4
- redhat codeready linux builder eus9.6
Versions reported by the vendor
Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.
Red Hat Red Hat Enterprise Linux 6
- all versionsunknown
Red Hat Red Hat Enterprise Linux 7
- all versionsunknown
- all versionsunknown
Red Hat Red Hat Enterprise Linux 8
- 0:2.28-225.el8_8.6 and laternot affected · rpm
- 0:2.28-225.el8_8.6 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 8.6 Extended Update Support
- 0:2.28-189.6.el8_6 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9
- 0:2.34-60.el9_2.7 and laternot affected · rpm
- 0:2.34-60.el9_2.7 and laternot affected · rpm
Red Hat Red Hat Enterprise Linux 9.0 Extended Update Support
- 0:2.34-28.el9_0.4 and laternot affected · rpm
Red Hat Red Hat Virtualization 4 for Red Hat Enterprise Linux 8
- 0:2.28-189.6.el8_6 and laternot affected · rpm
- 0:4.5.3-10.el8ev and laternot affected · rpm
- 0:4.5.3-202312060823_8.6 and laternot affected · rpm
sourceware.org/git/glibc.git glibc
- 2.34 and later · before 2.39affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | compat-libpthread-nonshared | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-all-langpacks | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-benchtests | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-common | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-devel | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-doc | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-gconv-extra | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-headers | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-aa | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-af | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-agr | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-ak | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-am | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-an | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-anp | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-ar | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-as | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-ast | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-ayc | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-az | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-be | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-bem | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
| AlmaLinux:8 | glibc-langpack-ber | before 2.28-225.el8_8.6 | 2.28-225.el8_8.6 |
+96
Same product
gnu: all recordsOther highest-scoring records for the same primary product.
- CVE-2015-0235Heap-based buffer overflow in the __nss_hostname_digits_dots function in glibc 2.2, and other 2.x versions before 2.18, allows context-depen68This week
- CVE-2015-7547Multiple stack-based buffer overflows in the (1) send_dg and (2) send_vc functions in the libresolv library in the GNU C Library (aka glibc 60This week
- CVE-2024-2961The iconv() function in the GNU C Library versions 2.39 and older may overflow the output buffer passed to it by up to 4 bytes when converti55Plan
Published before and after this one in the same product
- ← EarlierCVE-2023-4806Sep 18, 2023 · Glibc: potential use-after-free in getaddrinfo()23Monitor
- ← EarlierCVE-2023-5156Sep 25, 2023 · Glibc: dos due to memory leak in getaddrinfo.c30Monitor
- Later →CVE-2023-6246Jan 31, 2024 · Glibc: heap-based buffer overflow in __vsyslog_internal()32Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Azure Linux 3.0 ARM | 2.38-6 · glibc | Microsoft (MSRC) |
| Azure Linux 3.0 x64 | 2.38-6 · glibc | Microsoft (MSRC) |
| CBL Mariner 2.0 ARM | 2.35-5 · glibc | Microsoft (MSRC) |
| CBL Mariner 2.0 x64 | 2.35-5 · glibc | Microsoft (MSRC) |
| almalinux:glibc | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-all-langpacks | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-benchtests | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-common | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-devel | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-doc | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-gconv-extra | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-headers | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-langpack-aa | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-langpack-af | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-langpack-agr | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:glibc-langpack-ak | 2.34-60.el9_2.7 · AlmaLinux:9 | Package registry (OSV) |
| debian:glibc | 2.36-9+deb12u3 · Debian:12 | Package registry (OSV) |
| opensuse:glibc | 2.38-4.1 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:glibc-benchtests-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-common-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-debugsource | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-devel | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-doc | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-gconv-extra-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-headers | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-locale-source | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-utils | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:glibc-utils-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libnsl-debuginfo | 0:2.34-60.el9_2.7 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
+1
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Metasploit module ×1
- Exploit-DB entry ×1
- Nuclei detection template ×1
- Proof-of-concept repository on GitHub ×22
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | local | 2026-02-11 |
| Metasploit module | exploit/linux/local/glibc_tunables_priv_escGlibc Tunables Privilege Escalation CVE-2023-4911 (aka Looney Tunables)exploit | 2023-10-03 |
| Nuclei detection template | Nuclei template CVE-2023-4911 | — |
| Proof-of-concept repository on GitHub | stars:15 | 2023-10-04 |
| Proof-of-concept repository on GitHub | stars:394 | 2023-10-04 |
| Proof-of-concept repository on GitHub | stars:167 | 2023-10-04 |
| Proof-of-concept repository on GitHub | stars:1 | 2023-10-08 |
| Proof-of-concept repository on GitHub | stars:0 | 2023-10-10 |
| Proof-of-concept repository on GitHub | stars:29 | 2023-10-10 |
| Proof-of-concept repository on GitHub | stars:19 | 2023-10-11 |
| Proof-of-concept repository on GitHub | stars:0 | 2023-10-14 |
| Proof-of-concept repository on GitHub | stars:43 | 2023-10-17 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Metasploit-1 d
- Published
- First PoCsame day
- CISA KEV+48 d
- TodayNov 2, 2026+1126 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Someone with local access to the system can trigger it.
- A low-privileged account is enough.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Local
- Attack complexity
- Low
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-122 · Heap-based Buffer OverflowCVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (19 more)Show less
- access.redhat.com/errata/RHSA-2023:5454
- access.redhat.com/errata/RHSA-2023:5455
- access.redhat.com/errata/RHSA-2023:5476
- access.redhat.com/errata/RHSA-2024:0033
- access.redhat.com/security/cve/CVE-2023-4911
- bugzilla.redhat.com/show_bug.cgi?id=2238352
- www.qualys.com/cve-2023-4911/
- www.openwall.com/lists/oss-security/2023/10/03/3
- www.openwall.com/lists/oss-security/2023/10/05/1
- www.openwall.com/lists/oss-security/2023/10/13/11
- www.openwall.com/lists/oss-security/2023/10/14/3
- www.openwall.com/lists/oss-security/2023/10/14/5
- www.openwall.com/lists/oss-security/2023/10/14/6
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/4DBUQRRPB47TC3NJOUIBVWUGFHBJAFDL/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/DFG4P76UHHZEWQ26FWBXG76N2QLKKPZA/
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/NDAQWHTSVOCOZ5K6KPIWKRT3JX4RTZUR/
- security.gentoo.org/glsa/202310-03
- security.netapp.com/advisory/ntap-20231013-0006/
- www.debian.org/security/2023/dsa-5514
Vendor advisories and official records. Exploit/PoC links are deliberately left out.