CVE-2026-43258 | alpha: fix user-space corruption during memory compaction

In the Linux kernel, the following vulnerability has been resolved: alpha: fix user-space corruption during memory compaction Alpha systems can suffer sporadic user-space crashes and heap corruption when memory compaction is enabled. Symptoms include SIGSEGV, glibc allocator failures (e.g. "unaligned tcache chunk"), and compiler internal errors. The failures disappear when compaction is disabled or when using global TLB invalidation. The root cause is insufficient TLB shootdown during page migration. Alpha relies on ASN-based MM context rollover for instruction cache coherency, but this alone is not sufficient to prevent stale data or instruction translations from surviving migration. Fix this by introducing a migration-specific helper that combines: - MM context invalidation (ASN rollover), - immediate per-CPU TLB invalidation (TBI), - synchronous cross-CPU shootdown when required. The helper is used only by migration/compaction paths to avoid changing global TLB semantics. Additionally, update flush_tlb_other(), pte_clear(), to use READ_ONCE()/WRITE_ONCE() for correct SMP memory ordering. This fixes observed crashes on both UP and SMP Alpha systems.

Published: 2026-05-06 Last update: 2026-05-11 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-2026-43258 is rated Low Risk (32.5/100): CVSS High severity, with low exploitation likelihood (EPSS 0.14%). 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-2026-43258

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 2026-06-15 0.02% 0.14% +0.12%
2 2026-05-07 — 0.02% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-43258

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Weakness enumeration for CVE-2026-43258

GitHub Security Advisory for CVE-2026-43258

GHSA-rj9j-qfgp-687w · Severity: high — In the Linux kernel, the following vulnerability has been resolved: alpha: fix user-space...

OS Trackers for CVE-2026-43258

vendor priority summary link
debian not yet assigned CVE-2026-43258 not yet assigned priority: Debian including 1 source packages (linux), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 3, open 2. https://security-tracker.debian.org/tracker/CVE-2026-43258
redhat — — https://access.redhat.com/security/cve/CVE-2026-43258
suse — — https://www.suse.com/security/cve/CVE-2026-43258/
ubuntu medium CVE-2026-43258 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 1048, ignored 173, needed 129, released 83, not-affected 10, needs-triage 5, pending 1. https://ubuntu.com/security/CVE-2026-43258

Affected software / configurations for CVE-2026-43258

Vendor Product Version Raw CPE
linux linux_kernel >= 2.6.16.1, < 6.12.75 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.13, < 6.18.16 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel >= 6.19, < 6.19.6 cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:-:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc2:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc3:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc4:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc5:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc6:*:*:*:*:*:*
linux linux_kernel 2.6.16 cpe:2.3:o:linux:linux_kernel:2.6.16:rc7:*:*:*:*:*:*

References for CVE-2026-43258

cvelogic Threat Intelligence