Libslirp: libslirp: heap buffer overflow in dhcpv6/tftp response builders on small interface mtu

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-95508
StatePUBLISHED
Assignerredhat
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-22 09:17:06 UTC
Updated2026-09-22 19:37:36 UTC
DescriptionA heap-based buffer overflow was found in the DHCPv6 and TFTP response builders of libslirp. When the host is configured with a small interface MTU, a guest-supplied DHCPv6 CLIENTID option or TFTP blksize option can overflow the reply buffer with attacker-controlled content and length, resulting in denial of service and potentially arbitrary code execution in the host process. The default interface MTU is not affected.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

EPSS: 0.004230000 probability, percentile 0.363060000 (date 2026-09-23)

Problem Types: CWE-787 | CWE-787 Out-of-bounds Write

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H
3.1CNACVSS7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Red Hat Red Hat Enterprise Linux 10 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 8 Not specified Not specified
CNA Red Hat Red Hat Enterprise Linux 9 Not specified Not specified
CNA Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified
CNA Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified
CNA Red Hat Red Hat OpenShift Container Platform 4 Not specified Not specified

References

ReferenceSourceLinkTags
bugzilla.redhat.com/show_bug.cgi [email protected] bugzilla.redhat.com
access.redhat.com/security/cve/CVE-2026-95508 [email protected] access.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Red Hat would like to thank Stuart Thomas for reporting this issue. (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-09-16T00:00:00.000ZReported to Red Hat.
CNA2026-09-22T07:27:49.793ZMade public.

Workarounds

CNA: Do not configure SlirpConfig.if_mtu below the IPv6 minimum link MTU of 1280.

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