CVE-2026-5448

Memory corruption via oversized X.509 dates

Published Apr 9, 2026 · Updated Apr 9, 2026

Heap-based buffer overflow in wolfSSL before 5.9.1 allows attackers to corrupt memory through crafted X.509 certificate dates. CopyDecodedToX509 accepts date lengths up to 32 bytes, but wolfSSL_X509_notBefore and wolfSSL_X509_notAfter copy them at offset two into 32-byte buffers without reserving those two bytes. Exposure requires an application to call either compatibility API directly on attacker-controlled certificate data; wolfSSL TLS and certificate verification paths are unaffected.

CVSS severity2.3
Low
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in wolfSSL before 5.9.1 allows attackers to corrupt memory through crafted X.509 certificate dates. CopyDecodedToX509 accepts date lengths up to 32 bytes, but wolfSSL_X509_notBefore and wolfSSL_X509_notAfter copy them at offset two into 32-byte buffers without reserving those two bytes. Exposure requires an application to call either compatibility API directly on attacker-controlled certificate data; wolfSSL TLS and certificate verification paths are unaffected.

The record

CVE
CVE-2026-5448
Published
Apr 9, 2026
Updated
Apr 9, 2026
Vendor
wolfSSL
Product
wolfSSL
Classifications
CWE-122
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 9, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <5.9.1

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

wolfSSL · wolfSSLversion=0 <5.9.1

Published CVSS scores

2.3wolfSSL Inc.CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
4.3NIST NVDCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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