CVE-2026-115506
libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delay
- State
- Published
- Severity
- 8.7 High
- Published
- Oct 22, 2026
- Updated
- Oct 23, 2026
- Reserved
- Oct 22, 2026
Description
libexpat through 2.9.0 contains a denial of service vulnerability because billion laughs protection in accountingDiffTolerated() in xmlparse.c detects entity amplification too late. Attackers can supply a moderately sized XML document with a large DTD and nested entity expansions to consume tens of seconds of CPU per parse.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 4.0 | 8.7 High | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | VulnCheck |
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | VulnCheck |
Weaknesses
- CWE-776 Improper Restriction of Recursive Entity References in DTDs ('XML Entity Expansion')
Affected Products
| Product | Versions |
|---|---|
libexpatlibexpat |
|
References
- https://github.com/libexpat/libexpat/pull/1433patchissue-tracking
- https://github.com/libexpat/libexpat/issues/1160issue-tracking
- https://github.com/hannob/lolololexploit
- https://github.com/libexpat/libexpatproduct
- VulnCheck Advisory: libexpat through 2.9.0 Denial of Service via Billion Laughs Detection Delaythird-party-advisory
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