CVE-2026-31654 | mm/vma: fix memory leak in __mmap_region()

In the Linux kernel, the following vulnerability has been resolved: mm/vma: fix memory leak in __mmap_region() commit 605f6586ecf7 ("mm/vma: do not leak memory when .mmap_prepare swaps the file") handled the success path by skipping get_file() via file_doesnt_need_get, but missed the error path. When /dev/zero is mmap'd with MAP_SHARED, mmap_zero_prepare() calls shmem_zero_setup_desc() which allocates a new shmem file to back the mapping. If __mmap_new_vma() subsequently fails, this replacement file is never fput()'d - the original is released by ksys_mmap_pgoff(), but nobody releases the new one. Add fput() for the swapped file in the error path. Reproducible with fault injection. FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 1 CPU: 2 UID: 0 PID: 366 Comm: syz.7.14 Not tainted 7.0.0-rc6 #2 PREEMPT(full) Hardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: <TASK> dump_stack_lvl+0x164/0x1f0 should_fail_ex+0x525/0x650 should_failslab+0xdf/0x140 kmem_cache_alloc_noprof+0x78/0x630 vm_area_alloc+0x24/0x160 __mmap_region+0xf6b/0x2660 mmap_region+0x2eb/0x3a0 do_mmap+0xc79/0x1240 vm_mmap_pgoff+0x252/0x4c0 ksys_mmap_pgoff+0xf8/0x120 __x64_sys_mmap+0x12a/0x190 do_syscall_64+0xa9/0x580 entry_SYSCALL_64_after_hwframe+0x76/0x7e </TASK> kmemleak: 1 new suspected memory leaks (see /sys/kernel/debug/kmemleak) BUG: memory leak unreferenced object 0xffff8881118aca80 (size 360): comm "syz.7.14", pid 366, jiffies 4294913255 hex dump (first 32 bytes): 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... ff ff ff ff ff ff ff ff c0 28 4d ae ff ff ff ff .........(M..... backtrace (crc db0f53bc): kmem_cache_alloc_noprof+0x3ab/0x630 alloc_empty_file+0x5a/0x1e0 alloc_file_pseudo+0x135/0x220 __shmem_file_setup+0x274/0x420 shmem_zero_setup_desc+0x9c/0x170 mmap_zero_prepare+0x123/0x140 __mmap_region+0xdda/0x2660 mmap_region+0x2eb/0x3a0 do_mmap+0xc79/0x1240 vm_mmap_pgoff+0x252/0x4c0 ksys_mmap_pgoff+0xf8/0x120 __x64_sys_mmap+0x12a/0x190 do_syscall_64+0xa9/0x580 entry_SYSCALL_64_after_hwframe+0x76/0x7e Found by syzkaller.

Published: 2026-04-24 Last update: 2026-04-27 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-31654 is rated Low Risk (23.7/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-31654

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-04-25 — 0.02% —

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-31654

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.5 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 3.6 [email protected]

Weakness enumeration for CVE-2026-31654

GitHub Security Advisory for CVE-2026-31654

GHSA-cg89-59r4-qfhp · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: mm/vma: fix memory leak in...

OS Trackers for CVE-2026-31654

vendor priority summary link
debian unimportant CVE-2026-31654 unimportant priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2026-31654
redhat — — https://access.redhat.com/security/cve/CVE-2026-31654
suse medium — https://www.suse.com/security/cve/CVE-2026-31654/
ubuntu medium CVE-2026-31654 medium priority: Ubuntu including 161 source packages (linux, linux-allwinner-5.19, …), 1449 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1047, ignored 169, not-affected 144, released 84, needs-triage 5. https://ubuntu.com/security/CVE-2026-31654

Affected software / configurations for CVE-2026-31654

Vendor Product Version Raw CPE
linux linux_kernel >= 6.19.1, < 6.19.13 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.19 cpe:2.3:o:linux:linux_kernel:6.19:-:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc6:*:*:*:*:*:*
linux linux_kernel 7.0 cpe:2.3:o:linux:linux_kernel:7.0:rc7:*:*:*:*:*:*

References for CVE-2026-31654

cvelogic Threat Intelligence