wolfSSL up to 5.9.0 out-of-bounds write

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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7.0$0-$5k0.00+

Summaryinfo

A vulnerability was found in wolfSSL up to 5.9.0 and classified as critical. Affected by this issue is some unknown functionality. Executing a manipulation can lead to out-of-bounds write. This vulnerability is handled as CVE-2026-6679. The attack can be executed remotely. There is not any exploit available. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability was found in wolfSSL up to 5.9.0. It has been declared as critical. This vulnerability affects an unknown code. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. The CWE definition for the vulnerability is CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

A heap buffer overflow could occur in the DTLS 1.3 ACK serialization path before the connecting peer is authenticated. The buffer overflow was due to an integer truncation when computing the length of the ACK record-number list, causing an undersized buffer to be allocated and then overrun. This affects builds using DTLS 1.3 and wolfSSL version 5.9.0 and earlier. A fix was added to the 5.9.1 release.

The weakness was released by Nicholas Carlini. The advisory is shared for download at github.com. This vulnerability was named CVE-2026-6679 since 04/20/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA CVSS-B Score: 🔒
CNA CVSS-BT Score: 🔒
CNA Vector: 🔒

CVSSv3info

VulDB Meta Base Score: 7.3
VulDB Meta Temp Score: 7.0

VulDB Base Score: 7.3
VulDB Temp Score: 7.0
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds write
CWE: CWE-787 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

0-Day Time: 🔒

Patch: github.com

Timelineinfo

04/20/2026 CVE reserved
06/25/2026 +66 days VulDB entry created
06/26/2026 +0 days Advisory disclosed
06/26/2026 +0 days VulDB entry last update

Sourcesinfo

Product: github.com

Advisory: github.com
Researcher: Nicholas Carlini
Status: Confirmed

CVE: CVE-2026-6679 (🔒)
GCVE (CVE): GCVE-0-2026-6679
GCVE (VulDB): GCVE-100-374056

Entryinfo

Created: 06/26/2026 01:24
Changes: 06/26/2026 01:24 (66)
Complete: 🔍
Cache ID: 216::103

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