PoC Index

CVE-2023-38545

CRITICAL 9.8EPSS 78.5%

This flaw makes curl overflow a heap based buffer in the SOCKS5 proxyhandshake.When curl is asked to pass along the host name to the SOCKS5 proxy to allowthat to resolve the address instead of it getting done by curl itself, themaximum length that host name can be is 255 bytes.If the host name is detected to be longer, curl switches to local nameresolving and instead passes on the resolved address only. Due to this bug,the local variable that means "let the host resolve the name" could get thewrong value during a slow SOCKS5 handshake, and contrary to the intention,copy the too long host name to the target buffer instead of copying just theresolved address there.The target buffer being a heap based buffer, and the host name coming from theURL that curl has been told to operate with.

CVSS v3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS v3.1
8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS
78.48% chance of exploitation in the next 30 days, 100th percentile
Published
2023-10-18
Updated
2026-07-14

Proof-of-concept exploits (10)

References

Related