CVSS 3.1
8.2 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:NCVE-2026-64855 soapbar: verify_envelope_bsp accepts an unauthenticated embedded certificate (signature forgery / authentication bypass)
High (8.2) in hitoshyamamoto soapbar. EPSS 0.2% estimated probability of exploitation activity in the next 30 days.
On this page
soapbar is a SOAP library for Python — client, server, and WSDL handling. Prior to version 0.13.0, verify_envelope_bsp() derived its trust anchor from the message it was verifying. It read the X.509 certificate out of the caller-untrusted wsse:BinarySecurityToken, validated only that certificate's not-before / not-after dates, and then verified the signature against that same certificate. There was no CA-chain validation, no issuer/subject allowlist, and no pinning. A successful verify_envelope_bsp() therefore proved only that the envelope was signed by whoever supplied the embedded certificate — never that it was signed by a trusted party. An attacker who mints their own certificate, signs a forged envelope, and embeds that certificate in the token passes verification. Any consumer that treats a successful BSP verification as authentication can be impersonated (signature forgery / authentication bypass). verify_envelope() (which pins a caller-supplied x509_cert) was not affected — the flaw was specific to the BSP variant whose trust anchor came from the message. This issue has been patched in version 0.13.0.
Severity
- EPSS
- 0.2% estimated probability of exploitation activity in the next 30 days; 9th percentile. Scored 2026-11-13. A forecast for this CVE across the internet, not for your own systems.
- CISA's assessment (SSVC)
- Exploitation: none · Automatable: yes · Technical impact: partial, assessed 2026-11-12. From CISA's Vulnrichment in the CVE List: whether it is exploited, whether exploiting it can be automated, and how much control it gives.
- Published
- Modified
- Assigned by
- GitHub_M (CNA)
- NVD analysis
- Deferred: the NVD does not plan to analyze it
- Record from
- the NVD, synced
Ask an AI about this CVE
Show the prompt
Explain CVE-2026-64855 for an engineer deciding whether to act. Use https://cve.bz/api/public/cves/CVE-2026-64855?via=ask-ai-copy and https://cve.bz/cve/CVE-2026-64855?via=ask-ai-copy as the source of truth: what is affected and which versions fix it, whether it is in CISA KEV, public exploits, and its EPSS (an internet-wide 30-day estimate of exploitation activity, not a forecast for my systems). If they give no fixed versions, use the CVE record https://cveawg.mitre.org/api/cve/CVE-2026-64855 or the vendor advisory, not third-party mirrors. Tell me how to check whether I am affected and how to verify a fix. Cite the sources and say where they are uncertain.Opens a third-party assistant; its answer is its own, not cve.bz's. The prompt holds only this CVE's id and public links.
Badge for a README or a site
An image that stays current: it is drawn from the data each time it is fetched (a host that proxies images, as GitHub does, may show its copy for a while). Markdown:
[](https://cve.bz/cve/CVE-2026-64855)
HTML:
<a href="https://cve.bz/cve/CVE-2026-64855"><img src="https://cve.bz/cve/badge/CVE-2026-64855.svg" alt="CVE-2026-64855"></a>
Affected
Versions
From the CNA's record in the CVE List.
| Product | Affected |
|---|---|
| hitoshyamamoto soapbar | < 0.13.0 |
Attack patterns (CAPEC)
- CAPEC-459 Creating a Rogue Certification Authority Certificate Likelihood: Medium · Severity: Very High
- CAPEC-475 Signature Spoofing by Improper Validation Likelihood: Low · Severity: High
- CAPEC-463 Padding Oracle Crypto Attack Severity: High
The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.
History
- The NVD deferred its analysis
Changes since this site first stored the record. The same for every record: /api/public/changes.