HTML::Gumbo: Out-of-bounds Read
CVE-2025-15646 is a critical-severity out-of-bounds read vulnerability in HTML::Gumbo from BPS, with a CVSS 3.1 base score of 9.8 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 0.19 as the first without the flaw, so updating HTML::Gumbo to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.67% chance of exploitation within 30 days, higher than 53% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update HTML::Gumbo to 0.19 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 |
|---|---|---|---|
| BPS | HTML::Gumbo | before 0.19 | 0.19 |
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
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CISA (ADP).
Official description
HTML::Gumbo versions before 0.19 for Perl disclose heap memory via type confusion. Support for the <template> element was added to libgumbo 0.10.0 in 2015, but the walk_tree function in lib/HTML/Gumbo.xs was not updated to support it. The element was treated as a text-node, where strlen() over-reads the heap block that the pointer addresses. Any caller that runs parse() with the default format => 'string', or with format => 'tree', on input containing a <template> element serializes the over-read bytes into the returned result, disclosing bounded heap contents. format => 'callback' reaches a croak on the unhandled node type and is unaffected.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
Other references
Recent Out-of-bounds Read vulnerabilities
- 8.8 High severity
- 9.6 Critical severity
- 9.6 Critical severity
- 7.1 High severity
- 7.1 High severity
- 7.5 High severity
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