CVE-2026-23380 | tracing: Fix WARN_ON in tracing_buffers_mmap_close

In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in tracing_buffers_mmap_close When a process forks, the child process copies the parent's VMAs but the user_mapped reference count is not incremented. As a result, when both the parent and child processes exit, tracing_buffers_mmap_close() is called twice. On the second call, user_mapped is already 0, causing the function to return -ENODEV and triggering a WARN_ON. Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set. But this is only a hint, and the application can call madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the application does that, it can trigger this issue on fork. Fix it by incrementing the user_mapped reference count without re-mapping the pages in the VMA's open callback.

Published: 2026-03-25 Last update: 2026-04-24 Assigner: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Conclusion & alert: CVE-2026-23380 is rated Low Risk (23.5/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.02%). Mandatory action: 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-2026-23380

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 2026-03-25 0.02%

Full EPSS history (1 record total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-23380

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-2026-23380

GitHub Security Advisory for CVE-2026-23380

GHSA-q6xr-q445-2xxh · Severity: medium — In the Linux kernel, the following vulnerability has been resolved: tracing: Fix WARN_ON in...

OS Trackers for CVE-2026-23380

vendor priority summary link
debian unimportant CVE-2026-23380 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-2026-23380
redhat low https://access.redhat.com/security/cve/CVE-2026-23380
suse medium CVE-2026-23380 severity moderate: SUSE including 26 source package names (cluster-md-kmp-default, dlm-kmp-default, …), 230 product×package rows across 40 product lines (SUSE Linux Enterprise High Availability Extension 15 SP7, SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS, … (40 product lines)): Known Not Affected 230. https://www.suse.com/security/cve/CVE-2026-23380/
ubuntu medium CVE-2026-23380 medium priority: Ubuntu including 157 source packages (linux, linux-allwinner-5.19, …), 1413 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): DNE 1018, ignored 169, not-affected 122, released 83, needed 21. https://ubuntu.com/security/CVE-2026-23380

Affected software / configurations for CVE-2026-23380

Vendor Product Version Raw CPE
linux linux_kernel >= 6.10.1, < 6.12.77 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.18.17 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 6.19.7 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 6.10 cpe:2.3:o:linux:linux_kernel:6.10:-:*:*:*:*:*:*
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-2026-23380

cvelogic Threat Intelligence