CVE-2025-68262: crypto: zstd - fix double-free in per-CPU stream cleanup

Deferred
AliasesUBUNTU-CVE-2025-68262DEBIAN-CVE-2025-68262
Published 16-12-2025Last modified 11-05-2026

Vulnerability summary

CVE-2025-68262 is a vulnerability in linux with no CVSS score yet. EPSS estimates a 0.18% chance of exploitation in the next 30 days, higher than 8% of scored vulnerabilities.

Priority
Insufficient evidence

No CVSS vector published; no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
Not scored
010
No CVSS score recorded
EPSS score
0.18%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 8 · Related 8
OPENSUSE-SU-2025:15836-1OPENSUSE-SU-2026:10301-1USN-8094-1USN-8094-2USN-8094-3USN-8094-4

Timeline

  1. 16-12-2025
    PublishedVulnerability first disclosed.
  2. 11-05-2026
    Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: crypto: zstd - fix double-free in per-CPU stream cleanup The crypto/zstd module has a double-free bug that occurs when multiple tfms are allocated and freed. The issue happens because zstd_streams (per-CPU contexts) are freed in zstd_exit() during every tfm destruction, rather than being managed at the module level. When multiple tfms exist, each tfm exit attempts to free the same shared per-CPU streams, resulting in a double-free. This leads to a stack trace similar to: BUG: Bad page state in process kworker/u16:1 pfn:106fd93 page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x106fd93 flags: 0x17ffffc0000000(node=0|zone=2|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 0017ffffc0000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: nonzero entire_mapcount Modules linked in: ... CPU: 3 UID: 0 PID: 2506 Comm: kworker/u16:1 Kdump: loaded Tainted: G B Hardware name: ... Workqueue: btrfs-delalloc btrfs_work_helper Call Trace: <TASK> dump_stack_lvl+0x5d/0x80 bad_page+0x71/0xd0 free_unref_page_prepare+0x24e/0x490 free_unref_page+0x60/0x170 crypto_acomp_free_streams+0x5d/0xc0 crypto_acomp_exit_tfm+0x23/0x50 crypto_destroy_tfm+0x60/0xc0 ... Change the lifecycle management of zstd_streams to free the streams only once during module cleanup.

CVSS metrics

Risk metrics not yet published.

EPSS trend

Probability

0.18%

Chance of exploitation in the next 30 days

Percentile

8%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.18% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

No weakness data has been published for this record.

Affected systems

Version check

Known conditions: not stated in public data.

Ubuntu98 products
  • linux< 6.17.0-19.19
  • linux-allwinner-5.19All versions (No fix recorded)
  • linux-aws< 6.17.0-1009.9
  • linux-aws-5.0All versions (No fix recorded)
  • linux-aws-5.11All versions (No fix recorded)
Debian1 product
  • linux< 6.17.12-1
Linux1 product
  • linux≥ f5ad93ffb54119a8dc5e18f070624d4ead586969, < dc0f4509b0ed5d82bef78e058db0ac4df04d0695 | ≥ f5ad93ffb54119a8dc5e18f070624d4ead586969, < e983feaa79de1e46c9087fb9f02fedb0e5397ce6 | ≥ f5ad93ffb54119a8dc5e18f070624d4ead586969, < 48bc9da3c97c15f1ea24934bcb3b736acd30163d | 6.17

3 vendors · 100 products

References

13 links
Show all 13 references