bpf: Fix bpf_sk_select_reuseport() memory leak
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 5 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-401.
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bpf_sk_select_reuseport() memory leak As pointed out in the original comment, lookup in sockmap can return a TCP ESTABLISHED socket. Such TCP socket may have had SO_ATTACH_REUSEPORT_EBPF set before it was ESTABLISHED. In other words, a non-NULL sk_reuseport_cb does not imply a non-refcounted socket. Drop sk's reference in both error paths. unreferenced object 0xffff888101911800 (size 2048): comm "test_progs", pid 44109, jiffies 4297131437 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 80 00 01 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc 9336483b): __kmalloc_noprof+0x3bf/0x560 __reuseport_alloc+0x1d/0x40 reuseport_alloc+0xca/0x150 reuseport_attach_prog+0x87/0x140 sk_reuseport_attach_bpf+0xc8/0x100 sk_setsockopt+0x1181/0x1990 do_sock_setsockopt+0x12b/0x160 __sys_setsockopt+0x7b/0xc0 __x64_sys_setsockopt+0x1b/0x30 do_syscall_64+0x93/0x180 entry_SYSCALL_64_after_hwframe+0x76/0x7e
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Linux | Linux | 5.8 and later | 5.10.234, 5.15.177, 6.1.127, 6.6.74, 6.12.11, 6.13 | Patch available | CNA |
- Linux VendorLinux Affected 5.8 and later Fixed in 5.10.234, 5.15.177, 6.1.127, 6.6.74, 6.12.11, 6.13 Patch available CNA
CPE configurations NVD · 8
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | 5.8 to before 5.15.177; 5.16 to before 6.1.127; 6.2 to before 6.6.74; 6.7 to before 6.12.11 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* | 6.13 rc1 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* | 6.13 rc2 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* | 6.13 rc3 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* | 6.13 rc4 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:* | 6.13 rc5 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:* | 6.13 rc6 | Vulnerable | Linux |
| cpe:2.3:o:linux:linux_kernel:6.13:rc7:*:*:*:*:*:* | 6.13 rc7 | Vulnerable | Linux |
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* Versions 5.8 to before 5.15.177; 5.16 to before 6.1.127; 6.2 to before 6.6.74; 6.7 to before 6.12.11 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc1:*:*:*:*:*:* Versions 6.13 rc1 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc2:*:*:*:*:*:* Versions 6.13 rc2 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc3:*:*:*:*:*:* Versions 6.13 rc3 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc4:*:*:*:*:*:* Versions 6.13 rc4 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc5:*:*:*:*:*:* Versions 6.13 rc5 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc6:*:*:*:*:*:* Versions 6.13 rc6 Vulnerable ·Linux
- cpe:2.3:o:linux:linux_kernel:6.13:rc7:*:*:*:*:*:* Versions 6.13 rc7 Vulnerable ·Linux
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.234, 5.15.177, 6.1.127, 6.6.74, 6.12.11, 6.13
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 8 | Affected | No fix planned: Out of support scope |
| Red Hat Enterprise Linux 9 | Affected | No fix planned: Will not fix |
Timeline
- 2026-10-02 Threatist record created from CVE-2025-21683
- 2026-10-03 Alias added: GHSA-fjfj-r96f-8hqw
References
Patch 6
- https://git.kernel.org/stable/c/bb36838dac7bb334a3f3d7eb29875593ec9473fc
- https://git.kernel.org/stable/c/0ab52a8ca6e156a64c51b5e7456cac9a0ebfd9bf
- https://git.kernel.org/stable/c/d0a3b3d1176d39218b8edb2a2d03164942ab9ccd
- https://git.kernel.org/stable/c/b02e70be498b138e9c21701c2f33f4018ca7cd5e
- https://git.kernel.org/stable/c/cccd51dd22574216e64e5d205489e634f86999f3
- https://git.kernel.org/stable/c/b3af60928ab9129befa65e6df0310d27300942bf
More Linux Kernel vulnerabilities
- TI-2025-26358 tls: fix handling of zero-length records on the rx_list KEVCVSS 3.1CRITICAL 9.8
- TI-2026-38352 netfilter: bridge: make ebt_snat ARP rewrite writable KEVCVSS 3.1HIGH 8.8
- TI-2013-05264 The (1) get_user and (2) put_user API functions in the Linux kernel before 3.5.5 on the… KEVCVSS 3.1HIGH 8.8
- TI-2022-00125 Integer overflow in kernel KEVCVSS 3.1HIGH 8.4
- TI-2013-01864 The perf_swevent_init function in kernel/events/core.c in the Linux kernel before 3.8.9… KEVCVSS 3.1HIGH 8.4
- TI-2021-05514 Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACE KEVCVSS 3.1HIGH 8.3
Sources
- CVE-2025-21683 · CVE Program
- CVE-2025-21683 · NVD
- FIRST EPSS
- GHSA-fjfj-r96f-8hqw · GitHub Advisory Database · CC BY 4.0
- CVE-2025-21683 · Red Hat security data · CC BY 4.0
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