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CVE-2026-50258Patch(redhat / enterprise_linux)

LOWCVSS 7.8 · HIGH

Signal is active with 1 mentions in latest observed window

Immediate actions

  • Patch redhat enterprise_linux systems immediately

Recommended action window: Monitor and triage in normal cycle

NVD description

A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. The X server has multiple stack buffers sized XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify or clamp non-canonical key types to XkbMaxShiftLevel. A client can change key types to excessive shift levels and trigger stack overflows. This is caused by an incomplete fix of CVE-2025-26597. This may be used to crash the server, or for privilege escalation if the X server runs as root.

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1.0/ 10 priority

Sources & remediation

Patch / fix
Vendor / third-party advisories
Other references
Weakness type (CWE)
CWE-121

Priority

LOW

Exploitation

NONE

PoC

NONE

Patch

AVAILABLE

Momentum

STABLE

Are you affected?

If you run products in this scope, you should treat this CVE as relevant to your environment.

  • enterprise_linux
  • x_server
  • xwayland

Threat summary

  • Patch or workaround signal is available
  • 2 mentions across 2 observed days
  • Momentum state: stable

What's happening

  • Patch or workaround mentioned in 2 signals
  • Technical details provided in 1 signal
  • Disclosure: 1 classified signal
  • Peaked 1d ago at 1 mentions (2026-06-06); latest day: 1
  • 2 total mentions across 2 days

Affected systems

Vendors
redhatx.org
Products
enterprise_linuxx_serverxwayland

4 versions affected across 3 products

Deep dive

Activity timeline2 mentions / 2d
00111Mentions · 2026-06-06: 1Mentions · 2026-06-08: 1Patch / Workaround · 2026-06-06: 1Patch / Workaround · 2026-06-08: 1Technical Details · 2026-06-08: 106-0606-08
Signal classification2 categories
Patch
150.0%
Disclosure
150.0%
Referenced assets4 URLs
Classification over time
DateTotalLabels
2026-06-061
Patch1
2026-06-081
Disclosure1
Full discourse2 posts
  • XLibre@XLibreDev
    Patch

    We released the #XLibre Xserver 25.0.0.24 and 25.1.6 on Jun 05 containing #security fixes for #CVE-2026-50256, CVE-2026-50257, CVE-2026-50258, CVE-2026-50259, CVE-2026-50260, CVE-2026-50261, CVE-2026-50262, and CVE-2026-50263. https://github.com/X11Libre/xserver/releases/tag/xlibre-xserver-25.0.0.24 https://github.com/X11Libre/xserver/releases/tag/xlibre-xserver-25.1.6

    Post summary

    The announcement details new XLibre Xserver releases that include patches for several CVEs, signaling a vendor-released fix.

    820215844.8K
    5.3K followersView on X
  • Hugo | DevOps | Cybersecurity 🇱🇻@HugoValters
    Disclosure

    CVE-2026-50258 - Stack buffer overflow in http://X.org X server and Xwayland. Incomplete fix for CVE-2025-26597 allows crash or privilege escalation via excessive shift levels. CVSS 7.8. No patch available. Mitigate NOW!. #CVE #Xorg #infosec https://www.valtersit.com/cve/CVE-2026-50258

    Post summary

    The post announces CVE-2026-50258, a stack buffer overflow in X.org and Xwayland, notes its CVSS score and lack of patch, and urges immediate mitigation.

    0000079
    921 followersView on X
CPE platform detail6 entries

6 of 6 entries

PartVendorProductVersionTarget SWTarget HW
OSredhatenterprise_linux10.0--
OSredhatenterprise_linux7.0--
OSredhatenterprise_linux8.0--
OSredhatenterprise_linux9.0--
Appx.orgx_server---
Appx.orgxwayland---

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