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CVE-2020-29367· NVD / CVE Program· CNA mitre

blosc2.c in Blosc C-Blosc2 through 2.0.0.beta.5 has a heap-based buffer overflow when there is a lack of space to write compressed data.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
Nov 27, 2020
Updated
Jun 16, 2026
EPSS
1.2% · 67th percentile
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Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.2%

Affected systems

VendorProduct
bloscc-blosc2

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • blosc c-blosc22.0.0

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
PyPIblosc2before 0.1.70.1.7
PyPIblosc2all versions—
SUSE:Package Hub 15 SP1bloscbefore 1.20.1-bp152.4.3.11.20.1-bp152.4.3.1
SUSE:Package Hub 15 SP1bloscbefore 1.20.1-bp152.4.3.11.20.1-bp152.4.3.1

Same product

blosc: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-3204c-blosc2 ndlz4x4.c ndlz4_decompress heap-based overflow
    39Monitor
  • CVE-2024-3203c-blosc2 ndlz8x8.c ndlz8_decompress heap-based overflow
    39Monitor
  • CVE-2023-37188C-blosc2 before 2.9.3 was discovered to contain a NULL pointer dereference via the function zfp_rate_decompress at zfp/blosc2-zfp.c.
    30Monitor
  • CVE-2023-37187C-blosc2 before 2.9.3 was discovered to contain a NULL pointer dereference via the zfp/blosc2-zfp.c zfp_acc_decompress.
    30Monitor
  • CVE-2023-37186C-blosc2 before 2.9.3 was discovered to contain a NULL pointer dereference in ndlz/ndlz8x8.c via a NULL pointer to memset.
    30Monitor
  • CVE-2023-37185C-blosc2 before 2.9.3 was discovered to contain a NULL pointer dereference via the function zfp_prec_decompress at zfp/blosc2-zfp.c.
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
opensuse:blosc1.20.1-bp152.4.3.1 · openSUSE:Leap 15.1Package registry (OSV)
PyPI:blosc20.1.7Package registry (OSV)
suse:blosc1.20.1-bp152.4.3.1 · SUSE:Package Hub 15 SP1Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records