Linux Kernel up to 6.18.43/7.1.7/7.2-rc5 Xsk Tx xsk_drop_skb deadlock

CVSS Meta Temp Score
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CTI Interest Score
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7.0$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.43/7.1.7/7.2-rc5. The impacted element is the function xsk_drop_skb of the component Xsk Tx. The manipulation leads to deadlock. This vulnerability is documented as CVE-2026-74560. The attack can be initiated remotely. There is not any exploit available.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 6.18.43/7.1.7/7.2-rc5. This issue affects the function xsk_drop_skb of the component Xsk Tx. The manipulation with an unknown input leads to a deadlock vulnerability. Using CWE to declare the problem leads to CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: xsk: fix buffer leak in xsk_drop_skb() for AF_XDP multi-buffer Tx This patch is inspired by the check[1] from sashiko. It says when overflow happens, the address of cq to be published is invalid. Actually the severer thing is the whole process of publishing the address of cq in this particular case is not right: it should truely publish the address and advance the cached_prod in cq as long as it reads descriptors from txq. The following is the full analysis. xsk_drop_skb() is called in three places, which all discard a partially built multi-buffer skb: 1) xsk_build_skb() -EOVERFLOW error path: packet exceeds MAX_SKB_FRAGS 2) __xsk_generic_xmit() post-loop cleanup: an invalid descriptor in the TX ring prevents the partial packet from completing 3) xsk_release(): socket close while xs->skb holds an incomplete packet In all three cases, the TX descriptors for the already-processed frags have been consumed from the TX ring (xskq_cons_release), and CQ slots have been reserved. However, xsk_drop_skb() calls xsk_consume_skb() which cancels the CQ reservations via xsk_cq_cancel_locked(). Since the buffer addresses never appear in the completion queue, userspace permanently loses track of these buffers. Fix this by letting consume_skb() trigger the existing xsk_destruct_skb destructor, which already submits buffer addresses to the CQ via xsk_cq_submit_addr_locked(). Note that cancelling the descriptors back to the TX ring (via xskq_cons_cancel_n) is not a appropriate option because an oversized packet that always exceeds MAX_SKB_FRAGS would be retried indefinitely, which is an obviously deadlock bug in the TX path. Also move the desc->addr assignment in xsk_build_skb() above the overflow check so that the current descriptor's address is recorded before a potential -EOVERFLOW jump to free_err, consistent with the zerocopy path in xsk_build_skb_zerocopy(). [1]: https://lore.kernel.org/all/[email protected]/

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-74560 since 08/15/2026. The exploitation is known to be easy. The attack may be initiated remotely. No form of authentication is needed for a successful exploitation. Technical details are known, but no exploit is available. The price for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026). MITRE ATT&CK project uses the attack technique T1499 for this issue.

Upgrading to version 6.18.44, 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 05e283466b86e0b25a5209a3eafe87aa9886064a/a0528ab6af62bf57153caaf8ea28e5fcb0e18fd4/a3c8382ebce4780c6b3ace2c09bc342313ac0186 is able to eliminate this problem.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Deadlock
CWE: CWE-833 / CWE-404
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.18.44/7.1.8/7.2-rc6
Patch: 05e283466b86e0b25a5209a3eafe87aa9886064a/a0528ab6af62bf57153caaf8ea28e5fcb0e18fd4/a3c8382ebce4780c6b3ace2c09bc342313ac0186

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74560 (🔒)
GCVE (CVE): GCVE-0-2026-74560
GCVE (VulDB): GCVE-100-390881

Entryinfo

Created: 08/15/2026 15:57
Changes: 08/15/2026 15:57 (59)
Complete: 🔍
Cache ID: 216::103

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