Quick answers
- Is CVE-2026-103501 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-103501 being exploited in the wild.
- How severe is CVE-2026-103501?
- Informational severity, published 10 October 2026.
- Which products and versions are affected?
- Apache DataSketches C++ 1.0.0-incubating through 5.2.0.
- Is there a fix for CVE-2026-103501?
- Yes: fixed in 5.3.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-103501 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-103501?
- Check whether you run Apache DataSketches C++ at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
How to fix
- Fixed in: 5.3.0
Technical details
The vulnerability exists in HLL sketch deserialization in LIST mode, where the coupon count from input is used to copy data into a fixed 8-entry buffer without validation. A malicious sketch can write up to 988 bytes past the buffer boundary. Only applications that deserialize HLL sketches from untrusted sources are affected; the attack vector requires providing malformed serialized data.
Affected products
- Apache DataSketches C++ 1.0.0-incubating through 5.2.0
Timeline
- 2026-10-10: disclosed