A vulnerability was found in libX11.
Noroxi assessment
Priority: Monitor (action score 30/100)
- The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
- Probability of exploitation in the next 30 days: 1.6% (FIRST EPSS); higher than 76.4% of all records.
- Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
- Fixed version: libX11 (AlmaLinux:8) 1.6.8-6.el8; libX11-common (AlmaLinux:8) 1.6.8-6.el8; libX11-devel (AlmaLinux:8) 1.6.8-6.el8.
- Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).
Low priority for now. Upgrade to libX11 (AlmaLinux:8) 1.6.8-6.el8; libX11-common (AlmaLinux:8) 1.6.8-6.el8; libX11-devel (AlmaLinux:8) 1.6.8-6.el8 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 · FIRST EPSS
A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the values provided for the Request, Event, or Error IDs are within the bounds of the arrays that those functions write to, using those IDs as array indexes. They trust that they were called with values provided by an Xserver adhering to the bounds specified in the X11 protocol, as all X servers provided by X.Org do. As the protocol only specifies a single byte for these values, an out-of-bounds value provided by a malicious server (or a malicious proxy-in-the-middle) can only overwrite other portions of the Display structure and not write outside the bounds of the Display structure itself, possibly causing the client to crash with this memory corruption.
- Published
- Jun 28, 2023
- Updated
- Jun 17, 2026
- EPSS
- 1.6% · 76th percentile
- CWE
- CWE-119
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 1.6%
Get told when this record changes
- Not in KEV: no record of exploitation in the wild
- No public exploit code on record
- 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 |
|---|---|---|
| x.org | libx11 | cpe:2.3:a:x.org:libx11 |
| redhat | enterprise linux | cpe:2.3:o:redhat:enterprise_linux |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- redhat enterprise linux8.0
- redhat enterprise linux9.0
- x.org libx11before 1.8.6
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.
n/a libX11
- libX11 1.8.6affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| AlmaLinux:8 | libX11 | before 1.6.8-6.el8 | 1.6.8-6.el8 |
| AlmaLinux:8 | libX11-common | before 1.6.8-6.el8 | 1.6.8-6.el8 |
| AlmaLinux:8 | libX11-devel | before 1.6.8-6.el8 | 1.6.8-6.el8 |
| AlmaLinux:8 | libX11-xcb | before 1.6.8-6.el8 | 1.6.8-6.el8 |
| AlmaLinux:9 | libX11 | before 1.7.0-8.el9 | 1.7.0-8.el9 |
| AlmaLinux:9 | libX11-common | before 1.7.0-8.el9 | 1.7.0-8.el9 |
| AlmaLinux:9 | libX11-devel | before 1.7.0-8.el9 | 1.7.0-8.el9 |
| AlmaLinux:9 | libX11-xcb | before 1.7.0-8.el9 | 1.7.0-8.el9 |
| Alpine:v3.15 | libx11 | before 1.7.3.1-r1 | 1.7.3.1-r1 |
| Alpine:v3.16 | libx11 | before 1.8-r1 | 1.8-r1 |
| Alpine:v3.17 | libx11 | before 1.8.4-r1 | 1.8.4-r1 |
| Alpine:v3.18 | libx11 | before 1.8.4-r4 | 1.8.4-r4 |
| Debian:10 | libx11 | before 2:1.6.7-1+deb10u3 | 2:1.6.7-1+deb10u3 |
| Debian:11 | libx11 | before 2:1.7.2-1+deb11u1 | 2:1.7.2-1+deb11u1 |
| Debian:12 | libx11 | before 2:1.8.4-2+deb12u1 | 2:1.8.4-2+deb12u1 |
| Debian:13 | libx11 | before 2:1.8.6-1 | 2:1.8.6-1 |
| openSUSE:Leap Micro 5.3 | libX11 | before 1.6.5-150000.3.30.1 | 1.6.5-150000.3.30.1 |
| Red Hat:enterprise_linux:8::appstream | libX11 | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-common | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-debuginfo | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-debugsource | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-devel | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-xcb | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
| Red Hat:enterprise_linux:8::appstream | libX11-xcb-debuginfo | before 0:1.6.8-6.el8 | 0:1.6.8-6.el8 |
+23
Same product
x.org: all recordsOther highest-scoring records for the same primary product.
- CVE-2021-31535LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code.42Plan
- CVE-2018-14600An issue was discovered in libX11 through 1.6.5.42Plan
- CVE-2018-14599An issue was discovered in libX11 through 1.6.5.40Plan
Published before and after this one in the same product
- ← EarlierCVE-2020-14344Aug 5, 2020 · An integer overflow leading to a heap-buffer overflow was found in The X Input Method (XIM) client was implemented in libX11 before version 26Monitor
- ← EarlierCVE-2020-14363Sep 11, 2020 · An integer overflow vulnerability leading to a double-free was found in libX11.31Monitor
- Later →CVE-2023-43785Oct 10, 2023 · Libx11: out-of-bounds memory access in _xkbreadkeysyms()22Monitor
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 |
|---|---|---|
| almalinux:libX11 | 1.7.0-8.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libX11-common | 1.7.0-8.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libX11-devel | 1.7.0-8.el9 · AlmaLinux:9 | Package registry (OSV) |
| almalinux:libX11-xcb | 1.7.0-8.el9 · AlmaLinux:9 | Package registry (OSV) |
| alpine:libx11 | 1.7.3.1-r1 · Alpine:v3.15 | Package registry (OSV) |
| debian:libx11 | 2:1.8.4-2+deb12u1 · Debian:12 | Package registry (OSV) |
| opensuse:libX11 | 1.6.5-150000.3.30.1 · openSUSE:Leap Micro 5.3 | Package registry (OSV) |
| red hat:libX11 | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-common | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-debuginfo | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-debugsource | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-devel | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-xcb | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| red hat:libX11-xcb-debuginfo | 0:1.7.0-8.el9 · Red Hat:enterprise_linux:9::appstream | Package registry (OSV) |
| suse:libX11 | 1.6.2-12.30.1 · SUSE:OpenStack Cloud 9 | Package registry (OSV) |
| suse:libX11 | 1.6.5-150000.3.30.1 · SUSE:Linux Enterprise Micro 5.3 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
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.
No dated events beyond publication.
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.
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).
National notice (Türkiye Cybersecurity Directorate / USOM)
Official security notices citing this record; remediation advice is on the agency's page.
- TR-23-0370 · Jun 21, 2023(Ubuntu Güvenlik Güncellemesi)
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- High
Weakness class (CWE)
CWE-119 · Improper Restriction of Operations within the Bounds of a Memory BufferCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Buffer ManipulationCAPEC-123likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- MIME ConversionCAPEC-42likelihood: High · High
- Overflow Binary Resource FileCAPEC-44likelihood: High · Very High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Show all references (4 more)Show less
Vendor advisories and official records. Exploit/PoC links are deliberately left out.