PuTTY Ed25519 Signature ecc-ssh.c eddsa_verify signature verification
Published Mar 22, 2026
6.3
MEDIUMCVSS 4.0
EPSS 0.24%
Description
A vulnerability was detected in PuTTY 0.83. Affected is the function eddsa_verify of the file crypto/ecc-ssh.c of the component Ed25519 Signature Handler. The manipulation results in improper verification of cryptographic signature. The attack may be performed from remote. The attack requires a high level of complexity. The exploitability is told to be difficult. The exploit is now public and may be used. The real existence of this vulnerability is still doubted at the moment. The patch is identified as af996b5ec27ab79bae3882071b9d6acf16044549. It is advisable to implement a patch to correct this issue. The vendor was contacted early, responded in a very professional manner and quickly released a patch for the affected product. However, at the moment there is no proof that this flaw might have any real-world impact.
Affected products
-
- Version 0.83StatusaffectedConstraints-
- Version
No data.
No Red Hat product state for this CVE.
No package ranges for this CVE.
Remediation
No remediation recorded yet.
References (10)
- http://www.openwall.com/lists/oss-security/2026/05/24/11
- https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-14301 Advisory
- https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=af996b5ec27ab79bae3882071b9d6acf16044549 patchPermissions Required
- https://github.com/py-thok/putty-ed25519-malleability-s-plus-l relatedThird Party Advisory
- https://github.com/py-thok/putty-ed25519-malleability-s-plus-l/blob/main/poc.py exploit
- https://vuldb.com/?ctiid.352429 signaturepermissions-requiredPermissions RequiredVDB Entry
- https://vuldb.com/?id.352429 vdb-entrytechnical-descriptionThird Party AdvisoryVDB Entry
- https://vuldb.com/?submit.775576 third-party-advisoryThird Party AdvisoryVDB Entry
- https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/eddsa-overlarge-s.html relatedThird Party Advisory
- https://www.rfc-editor.org/rfc/rfc8032#section-8.4 relatedTechnical Description
| Link | Providers | Tags |
|---|---|---|
| http://www.openwall.com/lists/oss-security/2026/05/24/11 | ||
| https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-14301 | Advisory | |
| https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=af996b5ec27ab79bae3882071b9d6acf16044549 | patchPermissions Required | |
| https://github.com/py-thok/putty-ed25519-malleability-s-plus-l | relatedThird Party Advisory | |
| https://github.com/py-thok/putty-ed25519-malleability-s-plus-l/blob/main/poc.py | exploit | |
| https://vuldb.com/?ctiid.352429 | signaturepermissions-requiredPermissions RequiredVDB Entry | |
| https://vuldb.com/?id.352429 | vdb-entrytechnical-descriptionThird Party AdvisoryVDB Entry | |
| https://vuldb.com/?submit.775576 | third-party-advisoryThird Party AdvisoryVDB Entry | |
| https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/eddsa-overlarge-s.html | relatedThird Party Advisory | |
| https://www.rfc-editor.org/rfc/rfc8032#section-8.4 | relatedTechnical Description |
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