CVE-2026-11972 tarfile opened in streaming mode mishandles EOF
High 8.2
Published
Updated
Check this codebase for CVE-2026-11972 and fix it if it is affected.
What it is: CVE-2026-11972 is a high-severity denial of service vulnerability in CPython, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-11972 in the wild and no public exploit code.
Affected packages and fixed versions:
- libpython (Bitnami): affected all versions; fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
- python (Bitnami): affected all versions; fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
- python-min (Bitnami): affected all versions; fixed in 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7
Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.
Reference: https://insights.sbomify.com/CVE-2026-11972/ (Markdown: https://insights.sbomify.com/CVE-2026-11972/index.md)
Attackers can cause excessive CPU consumption and service unavailability by exploiting improper EOF handling in Python's tarfile streaming mode.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-11972?
CVE-2026-11972 is a high-severity denial of service vulnerability in CPython, published on 23 Jun 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
When using the "tarfile" module with a file opened in "streaming mode" (mode="r|") the tarfile module did not properly handle EOF, making archive parsing take exponentially longer.
Which versions are affected by CVE-2026-11972?
3 open source packages ship an affected version, including libpython, python and python-min.
| Package | Affected | Fixed in |
|---|---|---|
libpython Bitnami | All versions | 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7 |
python Bitnami | All versions | 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7 |
python-min Bitnami | All versions | 3.10.21, 3.11.16, 3.12.14, 3.13.15, 3.14.7 |
Linux distribution packages (37)
python3.11 Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-debug Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-devel Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-idle Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-libs Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-test Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.11-tkinter Red Hat:hummingbird:1 | All versions | 0:3.11.15-4.4.hum1 |
python3.12 Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-debug Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-devel Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-idle Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-libs Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-test Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.12-tkinter Red Hat:hummingbird:1 | All versions | 0:3.12.13-3.3.hum1 |
python3.13 Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-debug Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-devel Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-freethreading Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-freethreading-debug Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-idle Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-libs Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-test Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.13-tkinter Red Hat:hummingbird:1 | All versions | 0:3.13.14-1.2.hum1 |
python3.14 Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-debug Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-devel Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-debug Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-devel Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-idle Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-libs Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-test Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-freethreading-tkinter Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-idle Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-libs Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-test Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
python3.14-tkinter Red Hat:hummingbird:1 | All versions | 0:3.14.6-1.2.hum1 |
How do I fix CVE-2026-11972?
Upgrade libpython to a fixed version for your release line: 3.10.21, 3.11.16, 3.12.14 or 3.13.15.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-11972 being exploited?
There is no known exploitation of CVE-2026-11972 in the wild and no public exploit code.
Sources
Also known as ALPINE-CVE-2026-11972, AZL-91248, BELL-CVE-2026-11972, BIT-libpython-2026-11972, BIT-python-2026-11972, BIT-python-min-2026-11972 and 29 more.