Vulnerability · Published Apr 9, 2026 · Assigned by wolfSSL
CVE-2026-5778Integer underflow leads to out-of-bounds access in sniffer ChaCha decrypt path.
Low 2.1
In plain English
A low-severity security flaw in wolfSSL from wolfSSL. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
Integer underflow in wolfSSL packet sniffer <= 5.9.0 allows an attacker to cause a program crash in the AEAD decryption path by injecting a TLS record shorter than the explicit IV plus authentication tag into traffic inspected by ssl_DecodePacket. The underflow wraps a 16-bit length to a large value that is passed to AEAD decryption routines, causing a large out-of-bounds read and crash. An unauthenticated attacker can trigger this remotely via malformed TLS Application Data records.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.23 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2026-5778 |
| Alpine:v3.24 | wolfssl | 5.9.1-r0 | ALPINE-CVE-2026-5778 |
| Debian:12 | wolfssl | no fix listed | DEBIAN-CVE-2026-5778 |
| Debian:13 | wolfssl | no fix listed | DEBIAN-CVE-2026-5778 |
| Ubuntu:22.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5778 |
| Ubuntu:24.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5778 |
| Ubuntu:25.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-5778 |
| Ubuntu:26.04:LTS | wolfssl | no fix listed | UBUNTU-CVE-2026-5778 |
| Ubuntu:26.10 | wolfssl | no fix listed | UBUNTU-CVE-2026-5778 |
Affected products (as reported)
Weakness: CWE-191 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N