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CVE.org (no NVD analysis yet)· CNA EEF

CVE-2026-105274: hex_core decompresses registry and Erlang term API responses without size limits

LowCVSS 2.1 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 8/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.44% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
  • Fixed version: erlang rebar3 3.27.3, 360838a22f5b3a88c0358207f2923059bcbb3afb; hexpm hex 2.5.2, d8b60eee97abb119d525306f048969a217d793a5; hexpm hex_core 0.20.0, ebe25d110717f6a3addba5232cd4a7dc1c76b628.

Low priority for now. Upgrade to erlang rebar3 3.27.3, 360838a22f5b3a88c0358207f2923059bcbb3afb; hexpm hex 2.5.2, d8b60eee97abb119d525306f048969a217d793a5; hexpm hex_core 0.20.0, ebe25d110717f6a3addba5232cd4a7dc1c76b628 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Improper Handling of Highly Compressed Data (Data Amplification) vulnerability in hexpm hex_core allows an untrusted repository mirror, or a server answering hex_core's API requests, to exhaust the memory of the Erlang VM running hex_core. The same code is vendored in Hex (mix_hex_repo, mix_hex_api) and rebar3 (r3_hex_repo, r3_hex_api). hex_repo:get_names/1, hex_repo:get_versions/1, hex_repo:get_package/2 and hex_repo:get_policy/2 decompress the registry response with zlib:gunzip/1 and decode the signed envelope before verifying its signature. A mirror doesn't have the repository's private key, but it chooses the compressed bytes, so a small response decompresses into an envelope of any size before the signature check rejects it. hex_api decodes responses with the application/vnd.hex+erlang content type through hex_safe_binary_to_term:safe_binary_to_term/1, which calls binary_to_term(Binary, [safe]). The safe option prevents atom creation, but it accepts compressed terms and doesn't limit the size of the decoded term, and the check that rejects functions and ports runs after the term has been built. The fix for CVE-2026-21619 added the safe option and that check without bounding the decoded size. This issue affects rebar3: from 3.9.1 before 3.27.3; hex: from 2.1.0 before 2.5.2 and from 2.6.0 onward; hex_core: from 0.1.0 before 0.20.0.

Published
Oct 12, 2026
Updated
Nov 11, 2026
EPSS
0.4% · 39th percentile

Report tools

JSON

Action score

8

Monitor

Low priority for now.

CVSS
8 / 40 · 2.1 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · EEF
2.1
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-105274

When you'll hear from us

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  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (EEF). Independent of NVD's CPE analysis and usually ahead of it.

  • erlang rebar3

    • 3.9.1 and later · before 3.27.3affected · semver
    • 209c02ec57c2cc3207ee0174c3af3675b8dc8f79 and later · before 360838a22f5b3a88c0358207f2923059bcbb3afbaffected · git

  • hexpm hex

    • 2.1.0 and later · before 2.5.2affected · semver
    • 2.6.0 and lateraffected · semver
    • 671f695ac548ed01f5828c2a739ecaa942b21007 and later · before d8b60eee97abb119d525306f048969a217d793a5affected · git

  • hexpm hex_core

    • 0.1.0 and later · before 0.20.0affected · semver
    • fbb6d9de472e5edb8d6fb6b32a91cb266137892e and later · before ebe25d110717f6a3addba5232cd4a7dc1c76b628affected · git

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12rebar3from 0—
Debian:14erlang-hexbefore 2.5.3-22.5.3-2
Debian:14rebar3before 3.27.3-13.27.3-1
Hexhex_corefrom 0.1.0 · before 0.20.00.20.0

Same product

erlang: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-13802Rebar3 versions 3.0.0-beta.3 to 3.13.2 are vulnerable to OS command injection via URL parameter of dependency specification.
    41Plan
  • CVE-2019-1000014Erlang/OTP Rebar3 version 3.7.0 through 3.7.5 contains a Signing oracle vulnerability in Package registry verification that can result in…
    36Monitor
  • CVE-2026-103060Path traversal in rebar3 via unvalidated dependency app names
    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
erlang rebar33.27.3Vendor (CNA)
erlang rebar3360838a22f5b3a88c0358207f2923059bcbb3afbVendor (CNA)
hexpm hex2.5.2Vendor (CNA)
hexpm hexd8b60eee97abb119d525306f048969a217d793a5Vendor (CNA)
hexpm hex_core0.20.0Vendor (CNA)
hexpm hex_coreebe25d110717f6a3addba5232cd4a7dc1c76b628Vendor (CNA)
debian:erlang-hex2.5.3-2 · Debian:14Package registry (OSV)
debian:rebar33.27.3-1 · Debian:14Package registry (OSV)
Hex:hex_core0.20.0Package 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.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 13, 2026+32 d
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.

Not on record for this CVE: variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
A
Scope
X

Weakness class (CWE)

CWE-409 · Improper Handling of Highly Compressed Data (Data Amplification)

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

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.

Change log

  1. SSVC exploitation— → none
  2. Exploit maturity— → none
  3. Fix✗ → ✓

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

References

Show all references (8 more)

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

All records