CVE-2026-53163: linux NULL Pointer Dereference
Vulnerability summary
CVE-2026-53163 is a medium (CVSS 5.5) NULL Pointer Dereference vulnerability in linux. EPSS estimates a 0.12% chance of exploitation in the next 30 days, higher than 1.8% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 37 · Related 37Timeline
- 25-06-2026PublishedVulnerability first disclosed.
- 24-07-2026Last modifiedVulnerability information updated.
Description
In the Linux kernel, the following vulnerability has been resolved: locking/rtmutex: Skip remove_waiter() when waiter is not enqueued syzbot triggered the following splat in remove_waiter() via FUTEX_CMP_REQUEUE_PI: KASAN: null-ptr-deref in range [0x0000000000000a88-0x0000000000000a8f] class_raw_spinlock_constructor remove_waiter+0x159/0x1200 kernel/locking/rtmutex.c:1561 rt_mutex_start_proxy_lock+0x103/0x120 futex_requeue+0x10e4/0x20d0 __x64_sys_futex+0x34f/0x4d0 task_blocks_on_rt_mutex() does not arm the waiter upon deadlock detection, leaving waiter->task nil, where 3bfdc63936dd ("rtmutex: Use waiter::task instead of current in remove_waiter()") made this fatal. Furthermore, rt_mutex_start_proxy_lock() should not be calling into remove_waiter() upon a successfully grabbing the rtmutex. 1a1fb985f2e2 ("futex: Handle early deadlock return correctly"), moved the remove_waiter() out of __rt_mutex_start_proxy_lock() (where 'ret' was only ever 0 or < 0) into the wrapper. Tighten this check to account for try_to_take_rt_mutex().
CVSS metrics
4 scores · 3 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated5.5MediumCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.12%
Chance of exploitation in the next 30 days
Percentile
2%
Versus all other CVEs
30-day change
0.00 pp
From 0.12% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu147 products
- linuxAll versions (No fix recorded) | < 5.15.0-198.208 | < 6.8.0-147.147 | < 7.0.0-31.31
- linux-allwinner-5.19All versions (No fix recorded)
- linux-awsAll versions (No fix recorded) | < 5.15.0-1117.124 | < 6.8.0-1067.70 | < 7.0.0-1012.12
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Chainguard12 products
- linux-aws-6.12< 6.12.96-r0
- linux-azure-6.12< 6.12.96-r0
- linux-azure-6.18< 6.18.38-r0
- linux-gcp-6.12< 6.12.96-r0
- linux-gcp-6.18< 6.18.38-r0
Linux2 products
- linux≥ f3fa3424bceb128d2be4b3745506b22844b87db7, < bfbc047ceb42c0e1fac8f3a155d4548a8bbe76b1 | ≥ 838ce5cb5d93c3ab8b27e75bc6ad905a94b752fd, < 4ffacf76a457b7ca8ac05f5df8740b0d8f53574a | ≥ d8cce4773c2b23d819baf5abedc62f7b430e8745, < 4afda3a1da02129568a3a2f1898aa13e6763bcba | ≥ 8a1fc8d698ac5e5916e3082a0f74450d71f9611f, < 6707d7e0b71748cb3cd95bad81dae5fe1b3c8f48 | ≥ 6d52dfcb2a5db86e346cf51f8fcf2071b8085166, < 5799f9bd7fee40370b93ab1ddf001cdc7017c14d | ≥ 3fb7394a837740770f0d6b4b30567e60786a63f2, < a388e3dfaf9538a680de5ed43a8ebb5dd45b6e53 | ≥ 88614876370aac8ad1050ad785a4c095ba17ac11, < 55363fa0a04524d11efeaadee734d2db1756ed27 | ≥ 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349, < 40a25d59e85b3c8709ac2424d44f65610467871e | ≥ 6.1.175, < 6.1.177 | ≥ 6.6.140, < 6.6.144 | ≥ 6.12.86, < 6.12.95 | ≥ 6.18.27, < 6.18.36 | ≥ 7.0.4, < 7.0.13
- linux_kernel≥ 6.1.175, < 6.1.177 | ≥ 6.6.140, < 6.6.144 | ≥ 6.12.86, < 6.12.95 | ≥ 6.18.27, < 6.18.36 | ≥ 7.0.4, < 7.0.13 | 7.1:rc1 | 7.1:rc2 | 7.1:rc3 | 7.1:rc4 | 7.1:rc5 | 7.1:rc6
Debian1 product
- linux< 6.1.177-1 | < 6.12.95-1 | < 7.0.13-1
4 vendors · 162 products
