CVE-2026-55999 (GCVE-0-2026-55999)

Vulnerability from cvelistv5 – Published: 2026-07-08 08:07 – Updated: 2026-07-09 03:55
VLAI
Title
xorg-server / xwayland glamor font atlas Heap Buffer Overflow
Summary
Local attackers with a X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.
Severity
8.5 (High)
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
SSVC
Exploitation: none Automatable: no Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-07-08 00:00 UTC
CWE
  • CWE-122 - Heap-based buffer overflow
Assigner
References
Impacted products
Vendor Product Version CPE status
X.Org xorg-server Affected: 0 , < 21.1.24 (rpm)
guessed Create a notification for this product.
X.Org xwayland Affected: 0 , < 24.1.13 (rpm)
guessed Create a notification for this product.
Date Public
2026-07-08 07:51
Credits
Anonymous working with Trend Micro Zero Day Initiative.
Show details on NVD website
To clipboard 

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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.