Linux Kernel up to 7.1.7 IPv6 fib6_rule_suppress use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k1.32

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.1.7 and classified as very critical. Impacted is the function fib6_rule_suppress of the component IPv6. The manipulation results in use after free. This vulnerability is identified as CVE-2026-74581. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.1.7. Affected is the function fib6_rule_suppress of the component IPv6. 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: net: ipv6: clear suppressed fib6 rule result fib6_rule_suppress() drops a suppressed route with ip6_rt_put_flags(), but leaves res->rt6 pointing at the released rt6_info. If no later rule supplies a replacement, fib6_rule_lookup() still sees res.rt6 and returns that stale dst to its caller. A suppressing rule can therefore leak a released route back to rt6_lookup(), and the next put hits rcuref_put_slowpath() from dst_release(). Clear res->rt6 when suppressing the route so suppressed lookups fall through to the null dst instead of reusing the released one.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-74581 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. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/21/2026).

Upgrading to version 5.10.265, 5.15.216, 6.1.183, 6.6.151, 6.12.103, 6.18.44 or 7.1.8 eliminates this vulnerability. Applying the patch 90c57310e266eb94e4a80d6b15a9ca131d2e82cb/5d29b286c9de0b309e94b9ed083aa1a2f429434f/354db6243eca59e9d187ffbf8b7955b044ce84dc/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa/9bad152c42b37499162367fe47867411e62fffa3/dc3ab04220667f254f4348572b2a0b3febff89fb/a341c091ca0bfae377747b1b59a3bd8ebe18a937/6aea62e433fe1b586202a5fee8b5807ce635e1d7 is able to eliminate this problem.

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Productinfo

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Version

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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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💳💳💳💳💳💳
💳💳💳💳💳💳
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

EPSS Score: 🔒
EPSS Percentile: 🔒

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 5.10.265/5.15.216/6.1.183/6.6.151/6.12.103/6.18.44/7.1.8
Patch: 90c57310e266eb94e4a80d6b15a9ca131d2e82cb/5d29b286c9de0b309e94b9ed083aa1a2f429434f/354db6243eca59e9d187ffbf8b7955b044ce84dc/6d98c70fe0ba8c7708bfd5b2a5174d2086775daa/9bad152c42b37499162367fe47867411e62fffa3/dc3ab04220667f254f4348572b2a0b3febff89fb/a341c091ca0bfae377747b1b59a3bd8ebe18a937/6aea62e433fe1b586202a5fee8b5807ce635e1d7

Timelineinfo

08/15/2026 CVE reserved
08/21/2026 +6 days Advisory disclosed
08/21/2026 +0 days VulDB entry created
08/21/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74581 (🔒)
GCVE (CVE): GCVE-0-2026-74581
GCVE (VulDB): GCVE-100-394146

Entryinfo

Created: 08/21/2026 18:58
Changes: 08/21/2026 18:58 (59)
Complete: 🔍
Cache ID: 216::103

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