CVE-2026-103501: Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). W

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CRITICAL 9.8REMOTEWATCHLIST

CVE-2026-103501 is a critical-severity flaw (CVSS 9.8) affecting affected software. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). When deserializing a sketch in LIST mode, from either a byte buffer or a stream, the coupon count was read from the input and used as the number of entries to copy into a fixed buffer of 8 entries, without checking it against the buffer's capacity. A crafted sketch could cause a write of up to 988 bytes past the end of this internal heap b

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.6% (top 54%)
CISA exploited list	No
Weakness	CWE-122, CWE-1284
Published	2026-10-10
Last modified	2026-10-16

Publisher (CNA): Apache Software Foundation

Last updated 2026-10-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Timeline

2026-10-10 11:17 UTCPublished CVE record published
2026-10-16 16:16 UTCUpdated Record last modified

Exact fixes by distribution

Fedora ELN · edk2 · FIXED · 20260812-12.eln159 · FEDORA-2026-e316b6370a · source

sudo dnf upgrade --advisory=FEDORA-2026-e316b6370a

Fedora 46 · perl-Mojo-DOM58 · FIXED · 3.003-1.fc46 · FEDORA-2026-d5412af3de · source

sudo dnf upgrade --advisory=FEDORA-2026-d5412af3de

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-103501?

No fixed release is listed yet. Watch the vendor advisory and apply any mitigation shown on this page.

Is CVE-2026-103501 being exploited?

CVE-2026-103501 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-103501 affect?

CVE-2026-103501 affects affected software. Severity is critical (CVSS 9.8). Heap buffer overflow in the HLL sketch deserialization of Apache DataSketches C++ (repo: datasketches-cpp). When deserializing a sketch in LIST mode, from either a byte buffer or a stream, the coupon count was read from the input and used

How urgent is CVE-2026-103501?

Priority 59/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

References

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