yacy_search_server: Improper Restriction of XML External Entity Reference
CVE-2026-82880 is a high-severity improper restriction of XML external entity reference vulnerability in yacy_search_server from Yacy, 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. Affected yacy_search_server versions: 1.941 and earlier. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.6% 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
- Check which version of yacy_search_server you run against the affected versions below, and install the vendor's latest release.
- 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 |
|---|---|---|---|
| Yacy | yacy_search_server | 1.941 and earlier | Not stated |
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
- NoneNothing can be modified.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N. Scored by CNA (vulncheck.com).
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA (vulncheck.com) |
| CVSS 3.1 | 7.5 | High | CNA (vulncheck.com) |
Official description
YaCy Search Server through 1.941 contains an XML external entity injection vulnerability in SVG, FreeMind, and OpenSearch parsers that fail to disable external entity resolution. Attackers can publish malicious documents with DOCTYPE declarations containing SYSTEM entities pointing to local files, causing the crawler to exfiltrate file contents into the searchable index.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Restriction of XML External Entity Reference
The product processes an XML document that can contain XML entities with URIs that resolve to documents outside of the intended sphere of control, causing the product to embed incorrect documents into its output.
How developers prevent this class of flaw
- Many XML parsers and validators can be configured to disable external entity expansion.
More Improper Restriction of XML External Entity Reference vulnerabilities (CWE-611)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: yes, technical impact: partial).
References
Patches and release notes
Other references
- github.com/yacy/yacy_search_server
- github.com/yacy/yacy_search_server/blob/Release_1.941/source/net/yacy/document/parser/images/svgParser.java#L…
- github.com/yacy/yacy_search_server/blob/Release_1.941/source/net/yacy/document/parser/mmParser.java#L66
- github.com/yacy/yacy_search_server/blob/Release_1.941/source/net/yacy/document/parser/xml/opensearchdescripti…
- github.com/yacy/yacy_search_server/issues/818
- vulncheck.com/advisories/yacy-search-server-through-1.941-xml-external-entity-injection-via-parsers
Recent Improper Restriction of XML External Entity Reference vulnerabilities
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
- 7.7 High severity
- 8.7 High severity
- 9.3 Critical severity
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