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Queue pointer corruption in libslirp lets guests crash the host

Priority LOW 28CWE-787Published · Updated

Key facts

Attack vector
Adjacent network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · High
Fix status
Deferred Red Hat: fix deferred

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-787 and the CVSS impact.

Summary

Libslirp in Red Hat Enterprise Linux 8, 9 and 10 and Red Hat OpenShift Container Platform 4 and 5 is affected. When moving a session between packet queues, if_output() unlinks and reinserts an arbitrary packet, corrupting queue pointers (CWE-787). A guest that generates burst traffic can crash the host networking process, causing a denial of service.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

A flaw was found in libslirp in if_output(). When moving a session from the fast queue to the batch queue, the code unlinked and reinserted an arbitrary packet via ifm->m_nextpkt instead of the session queue head, corrupting queue pointers. A guest generating burst traffic could crash the host networking process, causing a denial of service.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00265 18th percentileScored 2026-11-07
Fix Deferred Red Hat: fix deferred

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
Red HatRed Hat Enterprise Linux 10——No fix listedCNA
Red HatRed Hat Enterprise Linux 8——No fix listedCNA
Red HatRed Hat Enterprise Linux 9——No fix listedCNA
Red HatRed Hat OpenShift Container Platform 4——No fix listedCNA
Red HatRed Hat OpenShift Container Platform 4——No fix listedCNA
Red HatRed Hat OpenShift Container Platform 4——No fix listedCNA
Red HatRed Hat OpenShift Container Platform 5——No fix listedCNA
  • Red Hat Enterprise Linux 10 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Enterprise Linux 8 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat Enterprise Linux 9 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat OpenShift Container Platform 4 VendorRed Hat Affected — Fixed in — No fix listed CNA
  • Red Hat OpenShift Container Platform 5 VendorRed Hat Affected — Fixed in — No fix listed CNA

CPE names CNA · 5

CPEVersionsRoleVendor
cpe:/a:redhat:enterprise_linux:1010—Red Hat
cpe:/a:redhat:enterprise_linux:88—Red Hat
cpe:/a:redhat:enterprise_linux:99—Red Hat
cpe:/a:redhat:openshift:44—Red Hat
cpe:/a:redhat:openshift:55—Red Hat
  • cpe:/a:redhat:enterprise_linux:10 Versions 10 — ·Red Hat
  • cpe:/a:redhat:enterprise_linux:8 Versions 8 — ·Red Hat
  • cpe:/a:redhat:enterprise_linux:9 Versions 9 — ·Red Hat
  • cpe:/a:redhat:openshift:4 Versions 4 — ·Red Hat
  • cpe:/a:redhat:openshift:5 Versions 5 — ·Red Hat

Remediation

The sources list no fixed version for Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9, Red Hat Enterprise Linux 10, Red Hat OpenShift Container Platform 4 and Red Hat OpenShift Container Platform 5. Red Hat lists no remediation plan for these products.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred

Timeline

  1. 2026-11-03 Threatist record created from CVE-2026-120831
  2. 2026-11-03 Alias added: GHSA-c4qr-qpmh-whrf
  3. 2026-11-03 Affected versions changed · Red Hat
  4. 2026-11-03 CVSS score added · Red Hat
  5. 2026-11-04 Priority changed: MEDIUM → LOW
  6. 2026-11-05 CISA SSVC decision points changed

References

  • TI-2019-15875 Protection mechanism failure in Jenkins Pipeline: Groovy Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-15874 Protection mechanism failure in Jenkins Script Security Plugin KEVCVSS 3.1CRITICAL 9.9
  • TI-2019-08259 Underflow in PHP-FPM can lead to RCE KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-05363 Code injection in Elastic Kibana KEVCVSS 3.1CRITICAL 10.0
  • TI-2019-03949 Out-of-bounds write in ESXi and Horizon DaaS KEVCVSS 3.1CRITICAL 9.8
  • TI-2018-16080 A code execution vulnerability exists in the Stapler web framework used by Jenkins 2.153… KEVCVSS 3.1CRITICAL 9.8
See all 7413 →

Sources