Hivex: hivex: denial of service via out-of-bounds read in big-data block processing
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Affects hivex v1.3.24 (latest release tag) and the master branch, where the same code is present Application reads a value's data through hivex_value_value on a big-data block, as used by libguestfs, virt-win-reg, guestfish, and hivexget
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 25/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
The hivex library, which is used to read and parse Windows registry hive files, is affected by this flaw. An attacker who supplies a specially crafted registry file can cause applications that process it to crash, resulting in a denial of service.
Read the original description
A flaw was found in hivex. By supplying a specially crafted Windows registry hive file, an attacker can trigger an out-of-bounds memory read when hivex parses registry values containing malformed large data block lists. This issue can cause the application processing the registry file to crash, resulting in a Denial of Service (DoS).
What to do
Check whether your setup matches what the bug needs.
Affects hivex v1.3.24 (latest release tag) and the master branch, where the same code is present Application reads a value's data through hivex_value_value on a big-data block, as used by libguestfs, virt-win-reg, guestfish, and hivexgetWorkaround: The checked facts give no workaround. Until a fix is available, limit use of the affected tools on registry files from untrusted sources, since the crash is the reported impact.
Timeline
- CVE published
- First seen by cve.now
- Record last updated
Affected versions
- hivex
Version range not reported
- hivex
Version range not reported
- hivex
Version range not reported
- virt-devel:rhel/hivex
Version range not reported
- virt:rhel/hivex
Version range not reported
- hivex
Version range not reported
Evidence 2
- Report
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-120740
What does this mean?
When hivex reads a big-data block in a Windows registry file, it can read memory past the end of the data it should stay within. This can crash the program processing the file, which is a denial of service.Source: bugzilla.redhat.com, access.redhat.com
Am I affected, and how do I check?
The checked facts list hivex v1.3.24, the latest release tag, and the master branch, which has the same code. Check the hivex version installed on your system, and whether your tools call hivex_value_value on big-data blocks, as libguestfs, virt-win-reg, guestfish, and hivexget do.Source: bugzilla.redhat.com, access.redhat.com
What should I do about it?
The checked facts do not name a fixed version. Check the upstream hivex project or your distributor for a patched release, and update once one is available.Source: bugzilla.redhat.com, access.redhat.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What if there's no patch?
The checked facts give no workaround. Until a fix is available, limit use of the affected tools on registry files from untrusted sources, since the crash is the reported impact.Source: bugzilla.redhat.com, access.redhat.com