DTLS service interruption via fragment-offset underflow
Published Apr 30, 2026 · Updated Aug 31, 2026
Out-of-bounds read in GnuTLS before 3.8.13 allows remote attackers to interrupt DTLS services via a malformed handshake fragment. parse_handshake_header accepts a zero-length fragment with a nonzero offset, after which _gnutls_parse_record_buffered_msgs underflows the offset range and copies beyond the record data. Exploitation requires a GnuTLS client or server to parse an attacker-controlled DTLS handshake; TLS-only consumers do not reach this path.
Summary
What happened
Out-of-bounds read in GnuTLS before 3.8.13 allows remote attackers to interrupt DTLS services via a malformed handshake fragment. parse_handshake_header accepts a zero-length fragment with a nonzero offset, after which _gnutls_parse_record_buffered_msgs underflows the offset range and copies beyond the record data. Exploitation requires a GnuTLS client or server to parse an attacker-controlled DTLS handshake; TLS-only consumers do not reach this path.
The record
- CVE
- CVE-2026-33845
- Published
- Apr 30, 2026
- Updated
- Aug 31, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat OpenShift Container Platform 4.16
- Classifications
- CWE-191, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 30, 2026CVE publishedPublication date reported by the CVE source.
- Aug 31, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Malformed DTLS zero-length fragment reproducerproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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