SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-31535

LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code.

CRITICAL 9.8EPSS 10.6%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 10.6%, higher than 96% of all known CVEs. Patch or mitigate before the next change window.

Description

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.

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
10.63% probability · 96th percentile
CISA KEV
Not listed
Weakness
CWE-120
Affected
x.org/libx11 · x.org/x window system · fedoraproject/fedora
Source
cve@mitre.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.