UBUNTU-CVE-2026-43258
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.
02 / AFFECTED SOFTWARE
Affected packages
120 explicit affected versions
37 explicit affected versions
6 explicit affected versions
10 explicit affected versions
10 explicit affected versions
13 explicit affected versions
13 explicit affected versions
5 explicit affected versions
165 explicit affected versions
10 explicit affected versions
51 explicit affected versions
4 explicit affected versions
45 explicit affected versions
13 explicit affected versions
13 explicit affected versions
26 explicit affected versions
7 explicit affected versions
7 explicit affected versions
7 explicit affected versions
11 explicit affected versions
50 explicit affected versions
12 explicit affected versions
19 explicit affected versions
10 explicit affected versions
6 explicit affected versions
24 explicit affected versions
36 explicit affected versions
26 explicit affected versions
191 explicit affected versions
7 explicit affected versions
39 explicit affected versions
13 explicit affected versions
43 explicit affected versions
35 explicit affected versions
18 explicit affected versions
44 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
51 explicit affected versions
1 explicit affected versions
21 explicit affected versions
16 explicit affected versions
10 explicit affected versions
47 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
11 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
1 explicit affected versions
7 explicit affected versions
16 explicit affected versions
12 explicit affected versions
12 explicit affected versions
40 explicit affected versions
16 explicit affected versions
27 explicit affected versions
33 explicit affected versions
10 explicit affected versions
38 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
26 explicit affected versions
9 explicit affected versions
29 explicit affected versions
13 explicit affected versions
12 explicit affected versions
40 explicit affected versions
19 explicit affected versions
39 explicit affected versions
33 explicit affected versions
23 explicit affected versions
10 explicit affected versions
11 explicit affected versions
18 explicit affected versions
5 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
26 explicit affected versions
39 explicit affected versions
35 explicit affected versions
46 explicit affected versions
13 explicit affected versions
45 explicit affected versions
16 explicit affected versions
49 explicit affected versions
3 explicit affected versions
18 explicit affected versions
41 explicit affected versions
12 explicit affected versions
27 explicit affected versions
42 explicit affected versions
8 explicit affected versions
5 explicit affected versions
8 explicit affected versions
10 explicit affected versions
13 explicit affected versions
7 explicit affected versions
8 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
45 explicit affected versions
37 explicit affected versions
49 explicit affected versions
14 explicit affected versions
38 explicit affected versions
9 explicit affected versions
11 explicit affected versions
38 explicit affected versions
17 explicit affected versions
121 explicit affected versions
4 explicit affected versions
1 explicit affected versions
13 explicit affected versions
43 explicit affected versions
10 explicit affected versions
8 explicit affected versions
44 explicit affected versions
14 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
18 explicit affected versions
38 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
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.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/dd5712f3379cfe760267cdd28ff957d9ab4e51c7
- https://ubuntu.com/security/CVE-2026-43258
- https://ubuntu.com/security/notices/USN-8492-1
- https://ubuntu.com/security/notices/USN-8492-2
- https://ubuntu.com/security/notices/USN-8492-3
- https://ubuntu.com/security/notices/USN-8492-4
- https://ubuntu.com/security/notices/USN-8492-5
- https://ubuntu.com/security/notices/USN-8497-1
- https://ubuntu.com/security/notices/USN-8498-1
- https://ubuntu.com/security/notices/USN-8499-1
- https://ubuntu.com/security/notices/USN-8606-1
- https://ubuntu.com/security/notices/USN-8619-1
- https://www.cve.org/CVERecord?id=CVE-2026-43258