Linux Kernel up to 7.2-rc5 vector_mmsg_rx use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k0.47+

Summaryinfo

A vulnerability labeled as very critical has been found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. The affected element is the function vector_mmsg_rx. The manipulation results in use after free. This vulnerability is reported as CVE-2026-74478. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 6.6.150/6.12.102/6.18.43/7.1.7/7.2-rc5. Affected is the function vector_mmsg_rx. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: um: vector: fix use-after-free in vector_mmsg_rx() When vector_mmsg_rx() discards a packet whose overlay header fails verify_header(), it frees the skb and continues the loop: if (header_check < 0) { dev_kfree_skb_irq(skb); vp->estats.rx_encaps_errors++; continue; } The normal and short-packet paths fall through to the bottom of the loop body, which clears the consumed slot and advances the cursors: (*skbuff_vector) = NULL; mmsg_vector++; skbuff_vector++; The verify_header() < 0 path skips that via continue, so the freed skb is left in skbuff_vector[] and the cursors do not advance. The next iteration reads the same slot, gets the freed skb, and frees it again, producing a refcount underflow / use-after-free in the RX path. Discard the slot the same way the other paths do before continuing. Only transports whose verify_header() can return negative are affected: GRE and L2TPv3 do so on a cookie/session-id mismatch (raw/tap do not), so any peer on such a transport can trigger it without authentication.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-74478 since 08/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 08/15/2026).

Upgrading to version 6.6.151, 6.12.103, 6.18.44, 7.1.8 or 7.2-rc6 eliminates this vulnerability. Applying the patch 4b9601595e8b6b5d18878cac0aeabc687d241111/67d58ab4f2ccf7145f3da07e025735a09c79de1b/180ff4c81faf01ec4e06082c9daa7c40518ead89/804b681002ead233abf49a3efd681f5468a835f9/af421e9aed3920c7ac88c24daa48606c7112feca is able to eliminate this problem.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
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 6.6.151/6.12.103/6.18.44/7.1.8/7.2-rc6
Patch: 4b9601595e8b6b5d18878cac0aeabc687d241111/67d58ab4f2ccf7145f3da07e025735a09c79de1b/180ff4c81faf01ec4e06082c9daa7c40518ead89/804b681002ead233abf49a3efd681f5468a835f9/af421e9aed3920c7ac88c24daa48606c7112feca

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-2026-74478 (🔒)
GCVE (CVE): GCVE-0-2026-74478
GCVE (VulDB): GCVE-100-390792

Entryinfo

Created: 08/15/2026 15:11
Changes: 08/15/2026 15:11 (58)
Complete: 🔍
Cache ID: 216::103

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