CVE-2026-3548
CVE-2026-3548 is a critical-severity vulnerability in Wolfssl with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.
Key facts
- Severity: Critical (CVSS 3.x base score 9.8)
- CVSS v4: 7.2
- EPSS exploit prediction: 0% (37th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-13150
- Weakness: CWE-787
- Affected product: Wolfssl
- Published:
- Last modified:
Description
Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.
Frequently asked questions
- What is CVE-2026-3548?
- Two buffer overflow vulnerabilities existed in the wolfSSL CRL parser when parsing CRL numbers: a heap-based buffer overflow could occur when improperly storing the CRL number as a hexadecimal string, and a stack-based overflow for sufficiently sized CRL numbers. With appropriately crafted CRLs, either of these out of bound writes could be triggered. Note this only affects builds that specifically enable CRL support, and the user would need to load a CRL from an untrusted source.
- How severe is CVE-2026-3548?
- CVE-2026-3548 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2026-3548 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-3548?
- CVE-2026-3548 affects Wolfssl. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-3548?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
- Does CVE-2026-3548 have an EU (EUVD) identifier?
- Yes. CVE-2026-3548 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-13150.
- When was CVE-2026-3548 published?
- CVE-2026-3548 was published on 2026-03-19 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*
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