High [CVE-2026-19654] Rsyslog: a configuration-dependent issue in rsyslog's optional imptcp input module can allow an unauthenticated remote peer to crash rsyslogd
This high-severity Red Hat Linux advisory covers CVE-2026-19654 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 6, Red Hat Enterprise Linux 7.
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Summary
A unauthenticated remote peer may lead rsyslogd to crash due to a flaw in the optional imptcp module. A crafted input sequence during oversize-frame recovery can cause an invalid internal message length and terminate rsyslogd.
No confidentiality or integrity impact, privilege escalation, or code execution has been identified. imtcp and the default imptcp framing modes are not affected. This vulnerability in rsyslog allows an unauthenticated peer to crash the rsyslogd deamon, resulting a a Denial-of-Service, by sending a crafted input sequence.
This happens because the malicious input ends creating an invalid internal message length, which crashes the rsyslogd receiving the input.
This vulnerability is only exploitable when the following conditions are met: * imptcp module is explicitly loaded * There's an imptcp listener using the non-default framing.delimiter.regex mode * The attacker is able to establish a TCP connection to the target listener Although this vulnerability has been rated as having an Important severity in upstream, the Red Hat Product Security team has rated it as having a MODERATE severity in supported Red Hat Products.
This happens because the conditions described above are not met in default configurations of the `rsyslog` package as shipped with Red Hat Enterprise Linux Versions. Weakness: CWE-125.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To mitigate this issue, users that are relying on the imptcp module can implement one of the following options: 1) Remove the framing.delimiter.regex from the affected 2) Disabled the affected `imptcp` listener or unload `imptcp` if it's not required 3) Restrict the network access to the listener to trusted senders only
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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