CVE-2026-64439

CRITICALPre-NVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

This critical-severity CVE scores 9.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.2%, top 94% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 5 sources updated this week
9.8EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 9.8Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

In the Linux kernel, the following vulnerability has been resolved:

crypto: krb5 - filter out async aead implementations at alloc

krb5_aead_encrypt(), krb5_aead_decrypt() in rfc3961_simplified.c and rfc8009_encrypt(), rfc8009_decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any negative return from crypto_aead_{encrypt,decrypt}() as terminal, falling through to kfree_sensitive(buffer). When the encrypt_name resolves to an async AEAD instance the request returns -EINPROGRESS, the buffer is freed while the backend's worker still holds a pointer, and the worker dereferences the freed slab on completion.

KASAN report under UML+SLUB with a synthetic async aead backend bound to krb5->encrypt_name:

BUG: KASAN: slab-use-after-free in t5_stub_complete+0x7d/0xc7

The helpers were written synchronously, so filter the async instances out at allocation time instead of plumbing crypto_wait_req() through every call site.

Reachable via net/rxrpc/rxgk.c, fs/afs/cm_security.c and net/ceph/crypto.c on systems with an async AEAD provider bound to the krb5 enctype name.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation0% × 40%
Automatability30% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
6%
KEV
Not listed

Published

July 25, 2026

Last Modified

July 27, 2026

Advisory Details (3)

Auto-updated Jul 27, 2026
No patch confirmed yet.
generic

crypto: krb5 - filter out async aead implementations at alloc - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/ef6feb77e2d91761427c5b773edc9c97e1b706ad
generic

crypto: krb5 - filter out async aead implementations at alloc - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/6c9dddeb582fde005360f4fe02c760d45ca05fb5
generic

crypto: krb5 - filter out async aead implementations at alloc - kernel/git/stable/linux.git - Linux kernel stable tree

https://git.kernel.org/stable/c/2b7bd6dccff14b8b632c5244f1fd506918077221

Vendor Advisories for CVE-2026-64439(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Data Freshness Timeline

(refreshed 14× in last 7d / 14× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-27 05:26 UTCEG score recompute
  2. 2026-07-27 05:26 UTCGHSA enrichment
  3. 2026-07-27 05:13 UTCEG score recompute▲ 9.80
  4. 2026-07-27 05:13 UTCGHSA enrichment
  5. 2026-07-27 05:12 UTCMITRE cvelistV5CVSS v3 → 9.8 · severity → CRITICAL
  6. 2026-07-26 14:54 UTCEPSS rescore
  7. 2026-07-26 14:54 UTCEPSS rescore
  8. 2026-07-26 02:47 UTCEG score recompute
  9. 2026-07-26 02:47 UTCGHSA enrichment
  10. 2026-07-25 14:18 UTCEPSS rescore
  11. 2026-07-25 14:18 UTCEPSS rescore
  12. 2026-07-25 10:39 UTCNVD update
  13. 2026-07-25 09:27 UTCEG score recompute
  14. 2026-07-25 09:21 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-64439?
CVE-2026-64439 is a critical vulnerability published on July 25, 2026. In the Linux kernel, the following vulnerability has been resolved: crypto: krb5 - filter out async aead implementations at alloc krb5aeadencrypt(), krb5aeaddecrypt() in rfc3961_simplified.c and rfc8009encrypt(), rfc8009decrypt() in rfc8009_aes2.c set a NULL completion callback and treat any…
When was CVE-2026-64439 disclosed?
CVE-2026-64439 was first published in the National Vulnerability Database on July 25, 2026, with the most recent update on July 27, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-64439 actively exploited?
CVE-2026-64439 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 93.8% of all scored CVEs.
What is the CVSS score of CVE-2026-64439?
CVE-2026-64439 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2026-64439?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-64439, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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