CVE-2026-122330: Blosc c-blosc2

Blosc c-blosc2 before 3.5.0 Divide-by-Zero via blosc2_schunk_get_slice_buffer()

CVSS 6.8 Medium

Published by the CVE Program (CNA: VulnCheck) at 5 Nov 2026, 15:11 UTC. agentprime has not analysed this yet, so whether it affects any app is not known. This CVE names a vendor and product rather than a package, so the lockfile check doesn’t match it.

Affected products, as the CNA wrote them
Vendor	Product	Versions
Blosc	c-blosc2 pkg:github/Blosc/c-blosc2	affected before 3.5.0 semver Other versions: unaffected

Identifiers

CVE-2026-122330

CNA

VulnCheck

Weakness (CWE)

CWE-369

Not analysed yet

We haven’t published our own analysis of this CVE. If a person reviews it, this page will say what’s affected and what has to be true for it to matter.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
6.8	Medium	4.0	CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	CNA (VulnCheck)Used for this record
5.5	Medium	3.1	CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H	CNA (VulnCheck)

CISA KEV Not listed.
EPSS No score.

Timeline

5 Nov 2026, 15:11 UTC Confirmed by the CVE List
5 Nov 2026, 15:24 UTC First seen by agentprime
5 Nov 2026, 16:17 UTC Confirmed by NVD

Sources

References from the CNA

github.com/Blosc/c-blosc2/issues/834 issue-tracking
github.com/Blosc/c-blosc2/commit/4fff1787408d94b895c6f9cb50f7925ad5919052 patch
github.com/Blosc/c-blosc2/blob/v3.4.1/blosc/schunk.c#L1662-L1700 technical-description
github.com/Blosc/c-blosc2/blob/v3.4.1/blosc/frame.c#L1214-L1227 technical-description
hackmd.io/@haindpwn/c-blosc2-schunk-slice-divide-by-zero third-party-advisory
github.com/Blosc/c-blosc2 product
www.vulncheck.com/advisories/blosc-c-blosc2-before-3.5.0-divide-by-zero-via-blosc2-schunk-get-slice-buffer third-party-advisory

Facts on this page come from the CVE List as the CNA published them, with CVSS from the sources named above, CISA KEV and FIRST EPSS. Vendors, products and versions are shown as the CNA wrote them. We don’t reproduce the CVE’s description.