CVE-2026-43258: Linux kernel · alpha: fix user-space corruption during memory compaction
Affects Linux kernelSource CVE Database V5
Not known to be exploited · CVSS 7.8 High · fixed in dd5712f3379cfe760267cdd28ff957d9ab4e51c7 : patch Linux kernel soon.
Data as of 26 Oct 2026, 13:07 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 6% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in dd5712f3379cfe760267cdd28ff957d9ab4e51c7, d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6, bab8d762a8dbb816b10011e13b87d1bca91e5f77 +2
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 6 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
Description
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.
References
- git.kernel.org/stable/c/5593c9b255ae73f57a8b5e696a660032acbd67da (opens in a new tab)
- git.kernel.org/stable/c/d4ca6ca2c6f5a1d19d9014c5b36d96637846b5d6 (opens in a new tab)
- git.kernel.org/stable/c/03e42b5f7ad4c2c3db8bd384bab7990d5d53c90f (opens in a new tab)
- git.kernel.org/stable/c/bab8d762a8dbb816b10011e13b87d1bca91e5f77 (opens in a new tab)
- git.kernel.org/stable/c/dd5712f3379cfe760267cdd28ff957d9ab4e51c7 (opens in a new tab)