9.8

CVE-2026-5264: DTLS 1.3 ACK heap buffer overflow

Analyzed
AliasesUBUNTU-CVE-2026-5264DEBIAN-CVE-2026-5264ALPINE-CVE-2026-5264
Published 09-04-2026Last modified 10-04-2026

Vulnerability summary

CVE-2026-5264 is a critical (CVSS 9.8) Heap-based Buffer Overflow vulnerability in wolfssl. EPSS estimates a 0.45% chance of exploitation in the next 30 days, higher than 38.8% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 8.3 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
0.45%
0%100%
Low · -0.15 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 09-04-2026
    PublishedVulnerability first disclosed.
  2. 10-04-2026
    Last modifiedVulnerability information updated.

Description

Heap buffer overflow in DTLS 1.3 ACK message processing. A remote attacker can send a crafted DTLS 1.3 ACK message that triggers a heap buffer overflow.

CVSS metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.45%

Chance of exploitation in the next 30 days

Percentile

39%

Versus all other CVEs

30-day change

Decrease -0.15 pp

From 0.59% 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

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine1 product
  • wolfssl< 5.9.1-r0
Debian1 product
  • wolfsslAll versions (No fix recorded)
Ubuntu1 product
  • wolfsslAll versions (No fix recorded)
Wolfssl1 product

4 vendors · 4 products

References

5 links