PatchTheCVECVE-2026-5778: Integer underflow in wolfSSL packet sniffer <= 5.9.0 allows an attacker to cause a program crash in the AEAD d
CVE-2026-5778 is a medium-severity flaw (CVSS 6.5) affecting wolfssl. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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 m
Why this priority
- No elevated risk signals yet
A fixed release or distro patch exists.
Risk facts
| CVSS score | 6.5 (Medium) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | Required |
| EPSS exploit chance | 0.2% (top 87%) |
| CISA exploited list | No |
| Weakness | CWE-191 |
| Published | 2026-04-09 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2026-5778?
wolfssl: upgrade to 5.9.1. Exact commands for each OS are on this page.
Is CVE-2026-5778 being exploited?
CVE-2026-5778 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2026-5778 affect?
CVE-2026-5778 affects wolfssl. Severity is medium (CVSS 6.5). 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_Decode
How urgent is CVE-2026-5778?
Priority 26/100. No elevated risk signals yet.
Software pages
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