[squid-users] FATAL: invalid pct-encoded triplet

[Alex Rousskov]

On 2026-02-05 09:44, Andrea Venturoli wrote:
> Hello.
> 
> Running Squid 7.3 on several boxes.
> In the last couple of days it has been crashing on one.
> 
> Last time I captured this in the logs:
>> 2026/02/05 15:22:10 kid1| WARNING: dns-mime-type ACL is used in 
>> context without an HTTP response. Assuming mismatch.
>>     current master transaction: master72
>> 2026/02/05 15:22:10 kid1| FATAL: invalid pct-encoded triplet
>>     exception location: Uri.cc(102) Decode
>>     current master transaction: master72
>> 2026/02/05 15:22:10| Removing PID file (/var/run/squid/squid.pid)
> 
> The first two lines are quite common.
> I searched for the subsequent messages, which seem to be the interesting 
> ones, but found nothing.

You are probably suffering from Bug 5501:
https://bugs.squid-cache.org/show_bug.cgi?id=5501


> I'll try to upgrade to 7.4 and possibly get a core dump, but if someone 
> has any hint in the meantime...

Squid v7.4 does not have the corresponding fix AFAICT, but you are 
welcome to try patching it as mentioned in the bug report.


HTH,

Alex.