CVE-2021-41131

CVE-2021-41131 is a high-severity vulnerability in Linuxfoundation The Update Framework with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-22.

Key facts

Description

python-tuf is a Python reference implementation of The Update Framework (TUF). In both clients (`tuf/client` and `tuf/ngclient`), there is a path traversal vulnerability that in the worst case can overwrite files ending in `.json` anywhere on the client system on a call to `get_one_valid_targetinfo()`. It occurs because the rolename is used to form the filename, and may contain path traversal characters (ie `../../name.json`). The impact is mitigated by a few facts: It only affects implementations that allow arbitrary rolename selection for delegated targets metadata, The attack requires the ability to A) insert new metadata for the path-traversing role and B) get the role delegated by an existing targets metadata, The written file content is heavily restricted since it needs to be a valid, signed targets file. The file extension is always .json. A fix is available in version 0.19 or newer. There are no workarounds that do not require code changes. Clients can restrict the allowed character set for rolenames, or they can store metadata in files named in a way that is not vulnerable: neither of these approaches is possible without modifying python-tuf.

Frequently asked questions

What is CVE-2021-41131?
python-tuf is a Python reference implementation of The Update Framework (TUF). In both clients (`tuf/client` and `tuf/ngclient`), there is a path traversal vulnerability that in the worst case can overwrite files ending in `.json` anywhere on the client system on a call to `get_one_valid_targetinfo()`. It occurs because the rolename is used to form the filename, and may contain path traversal characters (ie `../../name.json`). The impact is mitigated by a few facts: It only affects implementations that allow arbitrary rolename selection for delegated targets metadata, The attack requires the ability to A) insert new metadata for the path-traversing role and B) get the role delegated by an existing targets metadata, The written file content is heavily restricted since it needs to be a valid, signed targets file. The file extension is always .json. A fix is available in version 0.19 or newer. There are no workarounds that do not require code changes. Clients can restrict the allowed character set for rolenames, or they can store metadata in files named in a way that is not vulnerable: neither of these approaches is possible without modifying python-tuf.
How severe is CVE-2021-41131?
CVE-2021-41131 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity high, and availability none.
Is CVE-2021-41131 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41131?
CVE-2021-41131 affects Linuxfoundation The Update Framework. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-41131?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41131 published?
CVE-2021-41131 was published on 2021-10-19 and last updated on 2026-06-17.

References

Affected products (1)

More vulnerabilities in Linuxfoundation The Update Framework

All CVEs affecting Linuxfoundation The Update Framework →

Other CWE-22 (Path Traversal) vulnerabilities

Browse all CWE-22 (Path Traversal) vulnerabilities →