🐛 Prevent trailing {0} in RawData validation#700
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nevans merged 1 commit intoJun 9, 2026
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Zero-length literals are explicitly allowed by the RFCs and this did not
catch text that ends with `{0}` or `{0+}`. This leaves RawData able to
absorb the `CRLF` that ends the command, and thus absorb the following
command into itself.
Ultimately, we don't care if the `number64` is encoded correctly nor
whether it claims to be a binary literal. So I've simplified the regexp
by dropping `~?` and using `\d+` for the number.
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This was referenced Jun 9, 2026
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As part of the
RawDatavalidation that was added tov0.6.4, raw data was checked to ensure it doesn't end with a literal continuation. However the regexp was too strict. Zero-length literals are explicitly allowed by the RFCs, so this did not catch text that ends with{0}or{0+}. This leaves RawData able to absorb theCRLFthat ends the command, and thus absorb the following command into itself.Ultimately, we don't care if the
number64is encoded correctly nor whether it claims to be a binary literal. So I've simplified the regexp by dropping~?and using\d+for the number. (See also #680: the RFCs aren't strict about leading zeros fornumber64anyway.)Exploiting this will result in unexpected crashes and timeouts, which could be used to create a simple denial of service attack. This attack will present very similarly to common network issues or server issues which also result in commands hanging or unexpectedly raising exceptions. By itself, this does not allow command injection. But the confusion caused by these errors could lead to other downstream issues, especially in a multi-threaded environment.