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CVE Record

CVE-2026-34580: Botan has a certificate authentication bypass due to trust anchor confusion

Botan is a C++ cryptography library. In 3.11.0, the function Certificate_Store::certificate_known had a misleading name; it would return true if any certificate in the store had a DN (and subject key identifier, if set) matching that of the argument. It did not check that the cert it found and the cert it was passed were actually the same certificate. In 3.11.0 an extension of path validation logic was made which assumed that certificate_known only returned true if the certificates were in fact identical. The impact is that if an end entity certificate is presented, and its DN (and subject key identifier, if set) match that of any trusted root, the end entity certificate is accepted immediately as if it itself were a trusted root. , This vulnerability is fixed in 3.11.1.

CriticalCVSS 9.3Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

Botan 3.11.0 can mistakenly treat a presented end-entity certificate as trusted when its distinguished name, and subject key identifier if present, match a trusted root. That can bypass certificate authentication in software using this library. The source states the issue is fixed in Botan 3.11.1.

Executive priority

Treat this as urgent for any environment using Botan 3.11.0 in certificate-based authentication. The business risk is unauthorized trust decisions, not just service instability. Patch or obtain vendor confirmation quickly for externally reachable and identity-sensitive systems.

Technical view

Certificate_Store::certificate_known returned true on DN/SKI match instead of certificate identity. New 3.11.0 path validation logic assumed that meant the argument certificate was actually known. A matching end-entity certificate could therefore be accepted immediately as a trust anchor. This is CWE-295 certificate validation failure.

Likely exposure

Exposure is limited to applications or products using Botan 3.11.0 for certificate path validation. The provided affected range is >= 3.11.0 and < 3.11.1. No other products are identified in the bundle.

Exploitation context

The CVE has CVSS 4.0 score 9.3 with network attack vector, low complexity, no privileges, and no user interaction. The bundle does not report active exploitation, and KEV is false, so exploitation should not be stated as observed.

Researcher notes

The core issue is trust anchor confusion caused by matching DN/SKI metadata instead of certificate equality. The source bundle names only Botan 3.11.0 and fix 3.11.1. Evidence is insufficient to claim public exploit availability or downstream vendor impact beyond listed references.

Mitigation direction

  • Upgrade Botan to 3.11.1 or later where available.
  • Inventory applications and appliances that embed or statically link Botan.
  • Ask vendors whether their products include Botan 3.11.0 certificate validation code.
  • Prioritize internet-facing authentication, TLS, VPN, and mutual-TLS services.
  • If upgrade is delayed, follow Botan or vendor guidance rather than inventing compensating controls.

Validation and detection

  • Check package manifests, SBOMs, build files, and linked libraries for Botan 3.11.0.
  • Confirm runtime versions where applications bundle Botan outside the OS package manager.
  • Review certificate validation paths that rely on Botan trust stores.
  • Track vendor advisories for downstream products that may embed Botan.
  • Verify deployed fixes report Botan 3.11.1 or later.
Prepared
Confidence
high
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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cwe · low confidence lookup

CWE-295: Exact CWE lookup

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description · low confidence lookup

Credential and access behavior lookup

The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.

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cve · low confidence lookup

CVE-2026-34580 mapping review

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Vulnerability profileCVE Program record
Severity
Critical
CVSS
9.3 (4.0)
Known Exploited
No
Published

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

2CVSS vectors
5Timeline events
2ADP providers
5Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: yesTechnical Impact: total

CVSS vector scores

2 official scores

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
9.3CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N——GitHub_M
9.1CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N3.95.2redhat-SADP

Vulnerability scoring details

Base CVSS 4.0 score

9.3Critical
CVSS 4.0 vector shape for CVE-2026-34580Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. ADP timelineredhat-SADP

    Made public.

  3. CVE publishedCVE Program

    The CVE record was published.

  4. ADP timelineredhat-SADP

    Reported to Red Hat.

  5. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
redhat-SADPBotan: Botan: Certificate validation bypass due to incorrect certificate matching
other:Red Hat severity ratingcvssV3_1
  • 2026-04-07T22:01:51.201Z: Reported to Red Hat.
  • 2026-04-07T21:12:09.604Z: Made public.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
randombitbotan>= 3.11.0, < 3.11.1Listed
Weakness

CWE details

CWE-295

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-295 · source CWE mapping

Improper Certificate Validation

Improper Certificate Validation represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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