This report was translated by AI; nobody has reviewed the translation yet. Original language: Slovak.
[TLP:CLEAR] OpenSSL fixes the HollowByte vulnerability
OpenSSL fixes the HollowByte vulnerability, which allows an unauthenticated remote attacker to carry out a DoS attack on the target service by repeatedly sending specially crafted 11 B headers in the initial phase of a TLS request. On systems with the glibc library, the attacker can additionally cause persistent memory fragmentation. Detailed information about the vulnerability can be found at [1]. Fixed versions 4.0.1, 3.6.3, 3.5.7, 3.4.6 and 3.0.21 have been released for systems that take upstream packages. For stable and enterprise distributions, it is necessary to check in the package changelog whether the patch already implemented contains any of the pull requests 30792, 30793 or 30794 from the OpenSSL repository [1].
By CESNET, z.s.p.o. Ondrej Pavlovič on 21. 7. 2026.