CVE-2023-3138A vulnerability was found in libX11. The security flaw occurs because the functions in src/InitExt.c in libX11 do not check that the…
- 7.5HighCVSS base score
- 1.7%Exploitation in 30 daysEPSS · top 23% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By redhat
- 21 days later
· 21 days later
Published
- 13 months later
· 13 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Modified | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 1.7% · top 23% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.5.
Affected products
libX11
- affected libX11 1.8.6
References
References5
- https://access.redhat.com/security/cve/CVE-2023-3138 (opens in a new tab)x_transferred
- https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/304a654a0d57bf0f00d8998185f0360332cfa36c (opens in a new tab)x_transferred
- https://lists.x.org/archives/xorg-announce/2023-June/003406.html (opens in a new tab)x_transferred
- https://lists.x.org/archives/xorg-announce/2023-June/003407.html (opens in a new tab)x_transferred
- https://security.netapp.com/advisory/ntap-20231208-0008/ (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2023-43823 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2023-3138)Record last updated .