Bug 2492270 (CVE-2026-53091)

Summary:	CVE-2026-53091 kernel: net: pull headers in qdisc_pkt_len_segs_init()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, 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 the Linux kernel's handling of Generic Segmentation Offload (GSO) packet headers. This vulnerability occurs when the `qdisc_pkt_len_segs_init()` function does not properly pull headers into the expected memory location, which can lead to incorrect processing by network drivers. A remote attacker could exploit this by sending specially crafted malicious packets, potentially causing a denial of service (DoS) or other unexpected system behavior.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
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 2026-06-24 18:02:03 UTC

In the Linux kernel, the following vulnerability has been resolved:

net: pull headers in qdisc_pkt_len_segs_init()

Most ndo_start_xmit() methods expects headers of gso packets
to be already in skb->head.

net/core/tso.c users are particularly at risk, because tso_build_hdr()
does a memcpy(hdr, skb->data, hdr_len);

qdisc_pkt_len_segs_init() already does a dissection of gso packets.

Use pskb_may_pull() instead of skb_header_pointer() to make
sure drivers do not have to reimplement this.

Some malicious packets could be fed, detect them so that we can
drop them sooner with a new SKB_DROP_REASON_SKB_BAD_GSO drop_reason.

Comment 1 Mauro Matteo Cascella 2026-06-24 19:14:11 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062409-CVE-2026-53091-cb58@gregkh/T