CVE Catalog

CVE-2026-74630

HighCVSS 7.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.13%

3th percentile - higher than 3% of all known CVEs

Summary

In the Linux kernel, in6_dev_get() can resurrect an inet6_dev object after it has been freed. It reads dev->ip6_ptr under RCU and then unconditionally increments its refcount. If device teardown clears the pointer and drops the last reference between these operations, the increment can resurrect an object whose RCU free has already been queued, leading to use-after-free.

Risk Assessment

The risk includes use-after-free memory access, which could lead to system crashes or privilege escalation in the kernel.

Recommendation

It is recommended to apply the kernel patch that uses refcount_inc_not_zero() and returns NULL when the count reaches zero.

Other vulnerabilities in Linux kernel

See all
Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: ipv6: prevent in6_dev_get() from resurrecting inet6_dev in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally increments its refcount. Device teardown can clear the pointer and drop the last reference between these operations. The increment then resurrects an object whose RCU free has already been queued, so callers can use it after it is freed. Use refcount_inc_not_zero() and return NULL when the object has already reached zero. RCU keeps the memory accessible through the attempted reference acquisition, and a successful increment pins the object for the caller. An independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3) kernel reproduced the invalid reference acquisition as UID 1000: refcount_t: addition on 0; use-after-free. ip6_mc_source+0xef4/0x17e0 It was followed by the corresponding reference underflow in ip6_mc_source(). The supplied trace from the same unpatched revision additionally shows the access after the RCU read-side section ends: BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0 Write of size 8 at addr ffff888015b50240 by task poc/1219 Bug found and triaged by OpenAI Security Research and validated by Trail of Bits.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS