OSV-2025-803 Global-buffer-overflow in icaltime_day_of_year
Not scored
Published
Check this codebase for OSV-2025-803 and fix it if it is affected.
What it is: OSV-2025-803 is a memory corruption vulnerability in libical, published on 2 Oct 2025.
Exploitation: There is no known exploitation of OSV-2025-803 in the wild and no public exploit code.
Affected packages and fixed versions:
- libical (OSS-Fuzz): affected all versions; no fix listed
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/OSV-2025-803/ (Markdown: https://insights.sbomify.com/OSV-2025-803/index.md)
A global buffer overflow in the iCalendar library allows attackers to cause a denial of service via crafted input.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Not stated
- Victim action needed
- Not needed
- Fix
- None listed
What is OSV-2025-803?
OSV-2025-803 is a memory corruption vulnerability in libical, published on 2 Oct 2025.
Official description
OSS-Fuzz report: https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=448424495
Crash type: Global-buffer-overflow READ 4
Crash state:
icaltime_day_of_year
expand_bymonth_days
expand_year_days
Which versions are affected by OSV-2025-803?
1 open source package ship an affected version, including libical.
| Package | Affected | Fixed in |
|---|---|---|
libical OSS-Fuzz | All versions | None |
How do I fix OSV-2025-803?
No fix has been published for OSV-2025-803 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is OSV-2025-803 being exploited?
There is no known exploitation of OSV-2025-803 in the wild and no public exploit code.