LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed, e.g., to disable X server authorization completely. For example, if the victim encounters malicious terminal control sequences for color codes, then the attacker may be able to take full control of the running graphical session.
Metrics
Affected Vendors & Products
Advisories
| Source | ID | Title |
|---|---|---|
Debian DLA |
DLA-2666-1 | libx11 security update |
Debian DSA |
DSA-4920-1 | libx11 security update |
EUVD |
EUVD-2021-18433 | LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed, e.g., to disable X server authorization completely. For example, if the victim encounters malicious terminal control sequences for color codes, then the attacker may be able to take full control of the running graphical session. |
Ubuntu USN |
USN-4966-1 | libx11 vulnerability |
Ubuntu USN |
USN-4966-2 | libx11 vulnerability |
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Sun, 13 Jul 2025 13:45:00 +0000
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|---|---|---|
| Metrics |
epss
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Status: PUBLISHED
Assigner: mitre
Published:
Updated: 2024-08-03T23:03:33.270Z
Reserved: 2021-04-21T00:00:00
Link: CVE-2021-31535
No data.
Status : Modified
Published: 2021-05-27T13:15:08.240
Modified: 2024-11-21T06:05:51.990
Link: CVE-2021-31535
OpenCVE Enrichment
No data.
Debian DLA
Debian DSA
EUVD
Ubuntu USN