Botan: directoryName nameConstraint bypass via multi-AVA RDN flattening in matches_dn
- Exploited
- No known exploitation
- Fix
- Fixed in 3.13.0
- Who is exposed
- Not reported
Do first: Upgrade to a fixed version: 3.13.0.
- Last modified
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 5/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Botan, a C++ cryptography library, can be tricked into accepting a hostname that a name-constrained certificate should have blocked, when the certificate has no subjectAlternativeName extension. An attacker must control a name-constrained intermediate CA and needs high privileges to exploit it over the network, and the issue only affects deployments that use distinguished name constraints, which are uncommon outside internal PKIs.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
Botan is a C++ cryptography library. Prior to 3.13.0, Botan's X.509 Distinguished Name decoder flattens the Attribute-Value Assertions in each Relative Distinguished Name and loses multi-value RDN grouping before DN name-constraint enforcement. An attacker controlling a name-constrained intermediate CA can issue a certificate with a multi-value RDN whose first Common Name matches the permitted constraint and whose second Common Name is attacker-chosen, causing the constraint check to accept the flattened first value. If the certificate contains no subjectAlternativeName extension, the second Common Name can then be accepted as a hostname; Botan does not fall back to Common Name hostname matching when any subjectAlternativeName is present. The exposure is limited to deployments using DN name constraints, which are uncommon outside internal PKIs, and to certificates without a subjectAlternativeName. This issue is fixed in version 3.13.0.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure3/25Reachable over the network · Unknown: No advisory context yet
- Reach?/20Unknown. No tracked technology or package matched
- Severity2.1/10CVSS 2.1
- No patch0/5No signal
What would change the score
- Would score about 60 if added to CISA KEV
- Would score about 55 if CISA's SSVC rates exploitation active
- Would score about 24 if advisories confirm default setups are exposed
What to do
Upgrade to a fixed version: 3.13.0.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- randombit botan
fixed in 3.13.0
Evidence 3
- Advisory
- Repository
- Repository
Corrections
None so far.
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Questions about CVE-2026-48057
Is CVE-2026-48057 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
Which versions are affected by CVE-2026-48057?
botan: before 3.13.0.Source: cve.now feed data
How do I fix CVE-2026-48057?
Upgrade to a fixed version: 3.13.0.Source: cve.now feed data