CVE-2023-29409
Extremely large RSA keys in certificate chains can cause a client/server to expend significant CPU time verifying signatures.
Does this matter?
Lower severity and a low EPSS score (1.60%). Track it; it rarely justifies an emergency change on its own.
Description
Extremely large RSA keys in certificate chains can cause a client/server to expend significant CPU time verifying signatures. With fix, the size of RSA keys transmitted during handshakes is restricted to <= 8192 bits. Based on a survey of publicly trusted RSA keys, there are currently only three certificates in circulation with keys larger than this, and all three appear to be test certificates that are not actively deployed. It is possible there are larger keys in use in private PKIs, but we target the web PKI, so causing breakage here in the interests of increasing the default safety of users of crypto/tls seems reasonable.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
- EPSS
- 1.60% probability · 76th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-400
- Affected
- golang/go
- Source
- security@golang.org
EPSS 1.6% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://go.dev/cl/515257Patch
- https://go.dev/issue/61460Issue Tracking, Patch, Vendor Advisory
- https://groups.google.com/g/golang-announce/c/X0b6CsSAaYI/m/Efv5DbZ9AwAJMailing List, Vendor Advisory
- https://pkg.go.dev/vuln/GO-2023-1987Patch, Vendor Advisory
- https://security.gentoo.org/glsa/202311-09
- https://security.netapp.com/advisory/ntap-20230831-0010/
- https://go.dev/cl/515257Patch
- https://go.dev/issue/61460Issue Tracking, Patch, Vendor Advisory
- https://groups.google.com/g/golang-announce/c/X0b6CsSAaYI/m/Efv5DbZ9AwAJMailing List, Vendor Advisory
- https://pkg.go.dev/vuln/GO-2023-1987Patch, Vendor Advisory
- https://security.gentoo.org/glsa/202311-09
- https://security.netapp.com/advisory/ntap-20230831-0010/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.