HarfBuzz::Shaper: NULL Pointer Dereference
CVE-2026-0943 is a high-severity NULL pointer dereference vulnerability in HarfBuzz::Shaper from JV, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 0.032 as the first without the flaw, so updating HarfBuzz::Shaper to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.49% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update HarfBuzz::Shaper to 0.032 or a later version.
- Update Harfbuzz to 0.032 or a later version.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| JV | HarfBuzz::Shaper | before 0.032 | 0.032 |
| Jv | Harfbuzz | before 0.032 | 0.032 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- NoneNothing can be modified.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H. Scored by CISA (ADP).
Official description
HarfBuzz::Shaper versions before 0.032 for Perl contains a bundled library with a null pointer dereference vulnerability. Versions before 0.032 contain HarfBuzz 8.4.0 or earlier bundled as hb_src.tar.gz in the source tarball, which is affected by CVE-2026-22693.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: NULL Pointer Dereference
The product dereferences a pointer that it expects to be valid but is NULL.
How developers prevent this class of flaw
- For any pointers that could have been modified or provided from a function that can return NULL, check the pointer for NULL before use. When working with a multithreaded or otherwise asynchronous environment, ensure that proper locking APIs are used to lock before the check, and unlock when it has finished.
- Select a programming language that is not susceptible to these issues.
- Check the results of all functions that return a value and verify that the value is non-null before acting upon it.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- metacpan.org/release/JV/HarfBuzz-Shaper-0.032/changesProduct, Release Notes
Third-party and government advisories
- bugzilla.redhat.com/show_bug.cgi?id=2429296Third Party Advisory
- cve.org/CVERecord?id=CVE-2026-22693Third Party Advisory, VDB Entry
Recent NULL Pointer Dereference vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.5 High severity
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