CVE-2024-21645

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.

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.

CVE-2024-21645 has a CVSS score of 5.3 (Medium). The vector is network-reachable, no privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (0.5.0b3.dev77); upgrading removes the vulnerable code path.

Kodem intelligence

1. What is CVE-2024-21645? CVE-2024-21645 is a medium-severity security vulnerability in pyload-ng (pip), affecting versions < 0.5.0b3.dev77. It is fixed in 0.5.0b3.dev77.
2. How severe is CVE-2024-21645? CVE-2024-21645 has a CVSS score of 5.3 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of pyload-ng are affected by CVE-2024-21645? pyload-ng (pip) versions < 0.5.0b3.dev77 is affected.
4. Is there a fix for CVE-2024-21645? Yes. CVE-2024-21645 is fixed in 0.5.0b3.dev77. Upgrade to this version or later.
5. Is CVE-2024-21645 exploitable, and should I be worried? Whether CVE-2024-21645 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2024-21645 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2024-21645? Upgrade pyload-ng to 0.5.0b3.dev77 or later.