In glibc 2.26 and earlier there is confusion in the usage of getcwd() by realpath() which can be used to write before the destination buffer
In glibc 2.26 and earlier there is confusion in the usage of getcwd() by realpath() which can be used to write before the destination buffer leading to a buffer underflow and potential code execution.
- Published
- Jan 31, 2018
- Updated
- Jun 16, 2026
- EPSS
- 13.4% · 96th percentile
- CWE
- CWE-787
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
35
Monitor
Low priority for now.
- CVSS
- 31 / 40 · 7.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 4 / 30 · 13.4%
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| gnu | glibc | cpe:2.3:a:gnu:glibc |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| redhat | virtualization host | cpe:2.3:a:redhat:virtualization_host |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux server aus | cpe:2.3:o:redhat:enterprise_linux_server_aus |
| redhat | enterprise linux server eus | cpe:2.3:o:redhat:enterprise_linux_server_eus |
| redhat | enterprise linux server tus | cpe:2.3:o:redhat:enterprise_linux_server_tus |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- canonical ubuntu linux12.04
- canonical ubuntu linux14.04
- canonical ubuntu linux16.04
- canonical ubuntu linux17.10
- gnu glibcup to 2.26 inclusive
- redhat enterprise linux desktop7.0
- redhat enterprise linux server7.0
- redhat enterprise linux server aus7.6
- redhat enterprise linux server eus7.6
- redhat enterprise linux server tus7.6
- redhat enterprise linux workstation7.0
- redhat virtualization host4.0
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | glibc | before 2.26-4 | 2.26-4 |
| openSUSE:Tumbleweed | glibc | before 2.34-1.2 | 2.34-1.2 |
| Red Hat:enterprise_linux:7::client | glibc | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-common | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-debuginfo | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-debuginfo-common | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-devel | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-headers | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-static | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | glibc-utils | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| Red Hat:enterprise_linux:7::client | nscd | before 0:2.17-222.el7 | 0:2.17-222.el7 |
| SUSE:Linux Enterprise Desktop 12 SP2 | glibc | before 2.22-62.6.2 | 2.22-62.6.2 |
| SUSE:Linux Enterprise Desktop 12 SP2 | glibc | before 2.22-62.3.4 | 2.22-62.3.4 |
| SUSE:Linux Enterprise Server 12-LTSS | glibc | before 2.19-22.24.5 | 2.19-22.24.5 |
| SUSE:Linux Enterprise Server 12-LTSS | glibc | before 2.19-22.27.958 | 2.19-22.27.958 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | glibc | before 2.11.3-17.110.6.2 | 2.11.3-17.110.6.2 |
| SUSE:Linux Enterprise Software Development Kit 11 SP4 | glibc | before 2.11.3-17.110.3.1 | 2.11.3-17.110.3.1 |
| SUSE:OpenStack Cloud 6 | glibc | before 2.19-40.9.5 | 2.19-40.9.5 |
Same product
gnu: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-4911Glibc: buffer overflow in ld.so leading to privilege escalationKEV85Now
- 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 59Plan
- 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
- CVE-2018-11236stdlib/canonicalize.c in the GNU C Library (aka glibc or libc6) 2.27 and earlier, when processing very long pathname arguments to the realpa41Plan
- CVE-2015-8779Stack-based buffer overflow in the catopen function in the GNU C Library (aka glibc or libc6) before 2.23 allows context-dependent attackers41Plan
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 |
|---|---|---|
| debian:glibc | 2.26-4 · Debian:12 | Package registry (OSV) |
| opensuse:glibc | 2.34-1.2 · openSUSE:Tumbleweed | Package registry (OSV) |
| red hat:glibc | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-common | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-debuginfo | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-debuginfo-common | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-devel | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-headers | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-static | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:glibc-utils | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| red hat:nscd | 0:2.17-222.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| suse:glibc | 2.19-40.9.5 · SUSE:OpenStack Cloud 6 | Package registry (OSV) |
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 ×3
- Proof-of-concept repository on GitHub ×2
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 | 2018-06-13 |
| Exploit-DB entry | local | 2018-06-13 |
| Exploit-DB entry | local | 2018-01-16 |
| Metasploit module | exploit/linux/local/glibc_realpath_priv_escglibc 'realpath()' Privilege Escalationexploit | 2018-01-16 |
| Proof-of-concept repository on GitHub | stars:31 | 2018-02-07 |
| Proof-of-concept repository on GitHub | stars:0 | 2022-03-01 |
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.
- First PoC-15 d
- Metasploit-15 d
- Published
- TodaySep 30, 2026+3164 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.
No credits in the CNA record.
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-787 · Out-of-bounds WriteCVSS vector
CVSS:3.0/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.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- usn.ubuntu.com/3536-1/
- usn.ubuntu.com/3534-1/
- seclists.org/oss-sec/2018/q1/38
- www.securityfocus.com/bid/102525
- www.securitytracker.com/id/1040162
- access.redhat.com/errata/RHSA-2018:0805
- security.netapp.com/advisory/ntap-20190404-0003/
- www.halfdog.net/Security/2017/LibcRealpathBufferUnderflow/
Vendor advisories and official records. Exploit/PoC links are deliberately left out.