CVE-2023-3138
A vulnerability was found in libX11.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.66%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.66% probability · 76th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-119, CWE-787
- Affected
- x.org/libx11 · redhat/enterprise linux
- Source
- secalert@redhat.com
EPSS 1.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://access.redhat.com/security/cve/CVE-2023-3138Third Party Advisory
- https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/304a654a0d57bf0f00d8998185f0360332cfa36cPatch
- https://lists.x.org/archives/xorg-announce/2023-June/003406.htmlMailing List, Patch
- https://lists.x.org/archives/xorg-announce/2023-June/003407.htmlMailing List, Patch
- https://security.netapp.com/advisory/ntap-20231208-0008/
- https://access.redhat.com/security/cve/CVE-2023-3138Third Party Advisory
- https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/304a654a0d57bf0f00d8998185f0360332cfa36cPatch
- https://lists.x.org/archives/xorg-announce/2023-June/003406.htmlMailing List, Patch
- https://lists.x.org/archives/xorg-announce/2023-June/003407.htmlMailing List, Patch
- https://security.netapp.com/advisory/ntap-20231208-0008/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.