CVE-2026-5503

See a problem?
Please try reporting it to the source first.
Source
https://cve.org/CVERecord?id=CVE-2026-5503
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-5503.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-5503
Downstream
Published
2026-04-09T22:35:39.437Z
Modified
2026-07-16T03:48:42.285474051Z
Severity
  • 6.9 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
out-of-bounds write in TLSX_EchChangeSNI via attacker-controlled publicName
Details

In TLSXEchChangeSNI, the ctx->extensions branch set extensions unconditionally even when TLSXFind returned NULL. This caused TLSXUseSNI to attach the attacker-controlled publicName to the shared WOLFSSLCTX when no inner SNI was configured. TLSXEchRestoreSNI then failed to clean it up because its removal was gated on serverNameX != NULL. The inner ClientHello was sized before the pollution but written after it, causing TLSXSNI_Write to memcpy 255 bytes past the allocation boundary.

Database specific 
{
    "cwe_ids": [
        "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/5xxx/CVE-2026-5503.json",
    "cna_assigner": "wolfSSL"
}
References

Affected packages

Git / github.com/wolfssl/wolfssl

Affected ranges

Type
GIT
Repo
https://github.com/wolfssl/wolfssl
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
922d04b3568c6428a9fb905ddee3ef5a68db3108
Database specific 
{
    "cpe": "cpe:2.3:a:wolfssl:wolfssl:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "5.9.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "CPE_RANGE"
    ]
}

Affected versions

Other
WCv4-rng-stable
l
list
wolfEntropy1
wolfEntropy2d
WCv5.*
WCv5.0-RC10
WCv5.0-RC11
WCv5.0-RC12
WCv5.0-RC9
v0.*
v0.5
v1.*
v1.8.8.0
v1.9.0
v2.*
v2.0.2
v2.0.3
v2.0.6
v2.0.8
v2.0rc1
v2.0rc2
v2.0rc2b
v2.0rc3
v2.4.2
v2.4.6
v2.4.7
v2.6.0
v2.6.2
v2.7.0
v2.7.2
v2.8.0
v2.8.2
v2.8.3
v2.8.4
v2.8.5
v2.8.5a
v2.8.6
v2.9.0
v2.9.1
v2.9.2
v2.9.4
v3.*
v3.10.0-stable
v3.10.0a
v3.10.2-stable
v3.10.3
v3.11.0-stable
v3.11.1-tls13-beta
v3.12.0-stable
v3.12.2-stable
v3.13.0-stable
v3.13.2
v3.13.3
v3.14.0-stable
v3.14.0a
v3.14.0b
v3.14.2
v3.14.4
v3.15.0-stable
v3.15.3-stable
v3.15.5-stable
v3.15.5a
v3.15.6
v3.15.7-stable
v3.2.0
v3.2.4
v3.2.6
v3.3.0
v3.3.3
v3.4.0
v3.4.2
v3.4.6
v3.6.8
v3.6.9
v3.7.0
v3.7.1
v3.7.3
v3.8.0
v3.9.0
v3.9.1
v3.9.10-stable
v3.9.10b
v3.9.6
v3.9.6w
v3.9.8
v4.*
v4.0.0-stable
v4.1.0-stable
v4.2.0-stable
v4.2.0c
v4.3.0-stable
v4.4.0-stable
v4.5.0-stable
v4.6.0-stable
v4.7.0-stable
v4.7.1r
v4.8.0-stable
v5.*
v5.0.0-stable
v5.1.0-stable
v5.2.0-stable
v5.2.1
v5.3.0-stable
v5.4.0-stable
v5.5.0-stable
v5.5.1-stable
v5.5.2-stable
v5.5.3-stable
v5.5.4-stable
v5.6.0-stable
v5.6.2-stable
v5.6.3-stable
v5.6.4-stable
v5.6.6-stable
v5.7.0-stable
v5.7.2-stable
v5.7.4-stable
v5.7.6-stable
v5.8.0-stable
v5.8.2-stable
v5.8.4-stable
v5.9.0-stable

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-5503.json"