Security readout for executives and security teams
Plain-English summary
CVE-2026-4541 affects tinyssh’s Ed25519 signature handling. The reported impact is improper cryptographic signature verification, but exploitation is local, high-complexity, and rated low severity. Business urgency is limited unless tinyssh is installed on systems where untrusted local users can run code.
Executive priority
Treat as routine patching unless tinyssh runs on shared systems with untrusted local users. Prioritize confirmation of installed versions and apply the upstream fixed release during the next maintenance window.
Technical view
The flaw is reported in tinyssh/crypto_sign_ed25519_tinyssh.c within the Ed25519 Signature Handler. VulDB maps it to CWE-345 and CWE-347, with CVSS 3.1 score 2.5. Sources state an exploit has been published, but attack vector is local with low privileges and high attack complexity.
Likely exposure
Exposure is likely limited to environments running janmojzis tinyssh versions described as affected up to 20250501. The source bundle inconsistently lists 20260301 under affected versions while also naming it as the recommended fixed release.
Exploitation context
The sources say exploit material has been published, but CISA KEV is false and no active exploitation evidence is provided. The attack requires local execution, low privileges, no user interaction, and difficult exploitation conditions.
Researcher notes
Key uncertainty: the bundle lists 20260301 as affected while also recommending it as the fix. Avoid assuming remote authentication bypass from the summary alone; the published CVSS vector is local and integrity-only.
Mitigation direction
- Inventory systems running janmojzis tinyssh.
- Upgrade tinyssh to release 20260301 where applicable.
- Apply or verify commit 9c87269607e0d7d20174df742accc49c042cff17 if building from source.
- Check upstream tinyssh guidance for any later corrections or clarifications.
Validation and detection
- Confirm installed tinyssh version on managed hosts.
- Check whether local untrusted users can execute code on affected systems.
- Verify the patch commit is present in deployed source builds.
- Review GitHub issue 101 and pull request 102 for vendor context.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
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
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-345: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-347: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-4541 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Low
- CVSS
- 2.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
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.
CVSS vector scores
1 official scoreWe 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.
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C11.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
2.5LowVector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:L/A:N/E:P/RL:O/RC:C
Source materials
- CVE List V5 sourceCVE List V5
- VDB-352358 | janmojzis tinyssh Ed25519 Signature crypto_sign_ed25519_tinyssh.c signature verificationCVE reference · vdb-entry
- VDB-352358 | CTI Indicators (IOB, IOC, IOA)CVE reference · signature, permissions-required
- Submit #774687 | GitHub tinyssh 20250501 Cryptographic IssuesCVE reference · third-party-advisory
- https://github.com/janmojzis/tinyssh/issues/101CVE reference · issue-tracking, exploit
- https://github.com/janmojzis/tinyssh/pull/102CVE reference · issue-tracking, patch
- https://github.com/janmojzis/tinyssh/commit/9c87269607e0d7d20174df742accc49c042cff17CVE reference · patch
- https://github.com/janmojzis/tinyssh/releases/tag/20260301CVE reference · patch
- https://github.com/janmojzis/tinyssh/CVE reference · product
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Insufficient Verification of Data Authenticity
Insufficient Verification of Data Authenticity represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improper Verification of Cryptographic Signature
Improper Verification of Cryptographic Signature represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.