Public mode

No access to your tenant or devices. Every item links to its source. What this means

Some sources, documents or advisories need attention: 272/272 feeds/APIs · 469/469 docs · 8/9 advisories · checked 02:23 UTC Customize Public modeDiscuss ChangeIntel on Discord

zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()

Assessment

Severity
Moderate
CVSS base score
4.3CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L
Impact
Not stated
EPSS · 30-day forecast
No EPSS score collected
Public detection template
No Nuclei template is listed in the current collected catalog
Exploitation detected
Unknown: not stated by MSRC
Exploitability
Not assessed
Publicly disclosed
Unknown: not stated by MSRC
Customer action
Required: follow the MSRC remediation guidance
Component
Mariner
Weakness
CWE-125: Out-of-bounds Read
Issued by
VulnCheck
Published
29 Oct 2026 · October 2026
Last revised
29 Oct 2026
CVSS 3.1 base metricsRed raises the risk · green lowers it
Attack vector
NetworkAV:N
Attack complexity
LowAC:L
Privileges required
NonePR:N
User interaction
RequiredUI:R
Scope
UnchangedS:U
Confidentiality
NoneC:N
Integrity
NoneI:N
Availability
LowA:L

Updates that fix it

0 KBs

No KB listed

No KB update is listed in the collected MSRC record. Check the MSRC advisory for product releases and other remedies.

Affected products

Open Source Software
1 affected product
  • azl3 mtools 4.0.43-2 on Azure Linux 3.0

What changed

  1. Detection template: No Nuclei template listed · Customer action: Required: apply the update → Required: follow the MSRC remediation guidance · Public disclosure: No → Unknown: not stated by MSRC · Exploitation detected: Not reported by MSRC → Unknown: not stated by MSRC
Page history

Changes are dated when recorded; day views use the last saved version from that UTC day, and citations stay fixed.

Cite this version
Field-level log (5)

Up to 100 recent field edits are shown; older edits may be outside retention.

  1. 29 Oct 2026 · 20:19:26 UTC Public detection templateNo Nuclei template listed
  2. 29 Oct 2026 · 20:19:26 UTC EPSSNot scored → No EPSS score collected
  3. 29 Oct 2026 · 20:19:26 UTC Customer actionRequired: apply the update → Required: follow the MSRC remediation guidance
  4. 29 Oct 2026 · 20:19:26 UTC Publicly disclosedNo → Unknown: not stated by MSRC
  5. 29 Oct 2026 · 20:19:26 UTC Exploitation detectedNot reported by MSRC → Unknown: not stated by MSRC

Explore global source statements, affected packages and advisory history for CVE-2026-117556. The catalog has a separate collection scope from Microsoft release records.

Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-117556

Published

zchunk before 1.5.5 Heap Out-of-Bounds Read via read_preface()

zchunk before 1.5.5 contains a heap out-of-bounds read vulnerability in read_preface() in src/lib/header.c that passes the total header length instead of remaining bytes to compint parsing functions. Attackers can supply a crafted .zck file whose header ends inside a compressed integer, causing reads past the heap header buffer and crashing the application.

Source published
27 Oct 2026 13:07:51 UTC
Source modified
28 Oct 2026 16:17:15 UTC
Observed here
28 Oct 2026 17:46:48 UTC
Source terms
CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 5.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS 3.1 · 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

ChangeIntel

An IT change radar: releases, security, known issues, retirements, documentation changes, and service status from public sources. Every item links to supporting evidence; dates and statuses can change after they are read.

Sources read 31 Oct 02:23 UTC · 272 of 272 readable · 270 fully read · documentation 469/469 current