CVE-2019-18840 — Out-of-bounds Write in Wolfssl

CWE-787 — Out-of-bounds Write5 documents5 sources
Severity
7.5HIGHNVD
EPSS
0.4%
top 38.58%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
2
WolfsslDebian Wolfssl
Timeline
PublishedNov 9
Latest updateSep 12

Description

In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory accesses in parsing ASN.1 certificate data while handshaking. Specifically, there is a one-byte heap-based buffer overflow inside the DecodedCert structure in GetName in wolfcrypt/src/asn.c because the domain name location index is mishandled. Because a pointer is overwritten, there is an invalid free.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HExploitability: 3.9 | Impact: 3.6

Affected Packages3 packages

▶debiandebian/wolfssl< wolfssl 4.2.0+dfsg-3 (bookworm)
▶Debianwolfssl/wolfssl< 4.2.0+dfsg-3+3
▶NVDwolfssl/wolfssl4.1.0 — 4.2.0c

🔴Vulnerability Details

2
GHSA
GHSA-42mp-7xj4-8whx: In wolfSSL 4↗2022-05-24
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OSV
CVE-2019-18840: In wolfSSL 4↗2019-11-09
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📋Vendor Advisories

1
Debian
CVE-2019-18840: wolfssl - In wolfSSL 4.1.0 through 4.2.0c, there are missing sanity checks of memory acces...↗2019
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📄Research Papers

1
arXiv
Dynamic Vulnerability Patching for Heterogeneous Embedded Systems Using Stack Frame Reconstruction↗2025-09-12
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CVE-2019-18840 — Out-of-bounds Write in Debian Wolfssl | cvebase