Skip to main content
VulnerabilityPublished Updated

CVE-2026-74715: Linux kernel · bpf: Fix netns reference imbalance in conntrack kfuncs

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in fdeba03fea78407a8c52faa99177c9f7f29f90eb : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fdeba03fea78407a8c52faa99177c9f7f29f90eb, fb22bedf0c4f4f05bfa6e4a7ec0fd97bbdff9ce8, e5e060eb63d10b41ab60fd955649479d99b38210 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 22 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ aed8ee7feb44b6537af1e0b4f03365d42928be38, < fdeba03fea78407a8c52faa99177c9f7f29f90eb
Fixed in
  • fdeba03fea78407a8c52faa99177c9f7f29f90eb
LinuxLinuxAffected
  • ≥ aed8ee7feb44b6537af1e0b4f03365d42928be38, < fb22bedf0c4f4f05bfa6e4a7ec0fd97bbdff9ce8
Fixed in
  • fb22bedf0c4f4f05bfa6e4a7ec0fd97bbdff9ce8
LinuxLinuxAffected
  • ≥ aed8ee7feb44b6537af1e0b4f03365d42928be38, < e5e060eb63d10b41ab60fd955649479d99b38210
Fixed in
  • e5e060eb63d10b41ab60fd955649479d99b38210
LinuxLinuxAffected
  • ≥ aed8ee7feb44b6537af1e0b4f03365d42928be38, < 41731d4290400cb898f15f049ae4018d45415e69
Fixed in
  • 41731d4290400cb898f15f049ae4018d45415e69
LinuxLinuxAffected
  • ≥ aed8ee7feb44b6537af1e0b4f03365d42928be38, < 4af94462c0ca2187a02a1a6641020ae888c74d5c
Fixed in
  • 4af94462c0ca2187a02a1a6641020ae888c74d5c
LinuxLinuxAffected
  • =6.0
Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix netns reference imbalance in conntrack kfuncs The opts argument of the BPF conntrack kfuncs can point to a shared map value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read opts->netns_id separately when acquiring and releasing the network namespace reference. The reference imbalance can occur as follows: CPU 0 CPU 1 read opts->netns_id (-1) skip get_net_ns_by_id() write opts->netns_id (id) read opts->netns_id (id) put_net(net) /* no matching get */ The reverse transition leaks the reference. Repeating the unmatched put can destroy a live namespace and crash later users. The kernel reported: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700 Call Trace: __sys_bpf+0x1662/0x50c0 __x64_sys_bpf+0x73/0xb0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception Snapshot every input field of opts with READ_ONCE() before validating or using it. The netns_id snapshot keeps the namespace get/put pair balanced, while the other snapshots keep the remaining options from changing partway through an invocation. The individual reads can still observe an inconsistent combination during a concurrent update, but each selected field value remains stable for that invocation.

References

Community reviews

Loading reviews…