Bug 2565424 (CVE-2026-120830)

Summary:	CVE-2026-120830 libslirp: libslirp: out-of-bounds heap read in icmp_forward_error() leading to information disclosure
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in libslirp in icmp_forward_error(). When building an ICMP error response, the length of the quoted original IPv4 packet was taken from the IP header without clamping it to the actual buffer length. A truncated or malformed packet could cause an out-of-bounds heap read, leaking host memory into the ICMP error packet returned to a guest or container.	Story Points:	---
Clone Of:		Environment:
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Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-11-02 23:42:31 UTC

A flaw was found in libslirp in icmp_forward_error() in src/ip_icmp.c. When constructing an ICMP error packet, the length of the quoted original packet (s_ip_len) was derived from the IP header field ip_len without clamping it to the actual mbuf length (msrc->m_len). A truncated or malformed IPv4 packet could cause memcpy to read past the end of the source mbuf on the host heap, embedding residual host memory into the ICMP error packet returned over the virtual network interface. An unprivileged guest or container process able to send crafted packets through libslirp could disclose host heap contents.

Comment 1 Melissa Ing 2026-11-04 02:43:03 UTC

Resolved the following affects as AFFECTED/OOSS because their ps_update_streams are not in product-definitions active_ps_update_streams (Suggest Trackers will not offer them):

- rhel-9.9 / libslirp
- rhel-10.3 / libslirp
- rhivos-2.0.z / libslirp
- rhivos-2.0.z-core / libslirp

Active/default streams remain AFFECTED/DELEGATED with trackers filed.