CVE-2026-4115A vulnerability was detected in PuTTY 0.83.
Updated under an hour ago ()
Does this affect you?
It affects putty. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
Do this next
Free account, 1 product
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.
- CVSS
- 3.7 LOW (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N
- Weakness (CWE)
- CWE-345, CWE-347
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Jun 17, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
putty putty putty:putty | 0.83 | NVD |
References
- https://git.tartarus.org/?p=simon/putty.git;a=commitdiff;h=af996b5ec27ab79bae3882071b9d6acf16044549permissions-required
- https://github.com/py-thok/putty-ed25519-malleability-s-plus-lthird-party-advisory
- https://github.com/py-thok/putty-ed25519-malleability-s-plus-l/blob/main/poc.pyexploit
- https://vuldb.com/?ctiid.352429permissions-required, vdb-entry
- https://vuldb.com/?id.352429third-party-advisory, vdb-entry
- https://vuldb.com/?submit.775576third-party-advisory, vdb-entry
- https://www.chiark.greenend.org.uk/~sgtatham/putty/wishlist/eddsa-overlarge-s.htmlthird-party-advisory
- https://www.rfc-editor.org/rfc/rfc8032#section-8.4technical-description
- http://www.openwall.com/lists/oss-security/2026/05/24/11
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.