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PYSEC-2026-1818
No affected components available
Summary
A log injection vulnerability was identified in pyload. This vulnerability allows any unauthenticated actor to inject arbitrary messages into the logs gathered by pyload.
Details
pyload will generate a log entry when attempting to sign in with faulty credentials. This entry will be in the form of Login failed for user 'USERNAME'. However, when supplied with a username containing a newline, this newline is not properly escaped. Newlines are also the delimiter between log entries. This allows the attacker to inject new log entries into the log file.
PoC
Run pyload in the default configuration by running the following command
pyload
We can now sign in as the pyload user and view the logs at http://localhost:8000/logs.

Any unauthenticated attacker can now make the following request to inject arbitrary logs.
curl 'http://localhost:8000/login?next=http://localhost:8000/' -X POST -H 'Content-Type: application/x-www-form-urlencoded' --data-raw $'do=login&username=wrong\'%0a[2024-01-05 02:49:19] HACKER PinkDraconian THIS ENTRY HAS BEEN INJECTED&password=wrong&submit=Login'
If we now were to look at the logs again, we see that the entry has successfully been injected.

Impact
Forged or otherwise, corrupted log files can be used to cover an attacker’s tracks or even to implicate another party in the commission of a malicious act.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the integrity of the data.
Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.
The exploit probability is moderate. The vulnerability is likely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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