CVE Intelligence
Medium exploit reference

CVE-2026-27458 — LinkAce: Stored XSS in Atom Feed via CDATA Escape in List Description

LinkAce is a self-hosted archive to collect website links. Versions 2.4.2 and below have a Stored Cross-site Scripting vulnerability through the Atom feed endpoint for lists (/lists/feed). An authenticated user can inject a CDATA-breaking payload into a list description that escapes the XML CDATA section, injects a native SVG element into the Atom XML document, and executes arbitrary JavaScript directly in the browser when the feed URL is visited. No RSS reader or additional rendering context is required — the browser's native XML parser processes the injected SVG and fires the onload event handler. This vulnerability exists because the lists feed template outputs list descriptions using Blade's raw syntax ({!! !!}) without sanitization inside a CDATA block. The critical detail is that because the output sits inside <![CDATA[...]]>, an attacker can inject the sequence ]]> to close the CDATA section prematurely, then inject arbitrary XML/SVG elements that the browser parses and executes natively as part of the Atom document. This issue has been fixed in version 2.4.3.

Published Feb 21, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.3% (30-day exploitation probability)+3
  • Technical severity (medium)+3
  • CISA SSVC: exploitation "poc"+5
  • Automatable exploitation (SSVC)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.26%
ahead of 17% of scored CVEs · Oct 14, 2026
Affects
Kovah
LinkAce and 1 more
CVSS base
5.4
Medium · 3 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation
Proof of concept
none · proof-of-concept · active
Automatable
Yes
can an attacker script the kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

  • Documented patch — github.com (NIST National Vulnerability Database)
  • Documented mitigation — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Kovah LinkAce, Linkace Linkace).
  2. Apply the fixed version or the patch documented under Remediation.
  3. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  4. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Kovah LinkAce version < 2.4.3 Vulnerable CVE Program (cve.org) e CISA ADP
Linkace Linkace < 2.4.3 Vulnerable NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
Required
Scope
Changed
Confidentiality
Low
Integrity
Low
Availability
None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

ScoreVersionSeverityExpl.ImpactScored by
8.7 CVSS 4.0 High — — security-advisories@github.com via NIST National Vulnerability Database
8.7 CVSS 4.0 High — — GitHub_M via CVE Program (cve.org) e CISA ADP
5.4 CVSS 3.1 Medium 2.3 2.7 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N (score shown at the top: nvd@nist.gov)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-80

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.26%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

  • 2026
  • Affected products added · kovah/linkace
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • SSVC assessment updated
    Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
  • Record published
    Oct 13, 2026
  • Fix documented
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVSS changed · 5.4
    Oct 13, 2026 · NIST National Vulnerability Database
  • Source status changed · → Analyzed
    Oct 13, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 13, 2026 · NIST National Vulnerability Database
  • CVE published
    Feb 21, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

2 on the record

Elsewhere on this site

Kovah
every CVE for this vendor
CWE-80
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-45342 LinkAce: IDOR in Update Policies Allows Any Authenticated User to Overwrite Other Users' Links, Lists, Tags, and Notes May 28, 2026
  • CVE-2026-45344 LinkAce: Setup database password newline injection enables pre-auth RCE on uninitialized instances May 28, 2026
  • CVE-2026-45343 LinkAce - Stored XSS via Unsanitized SSO User's Name Rendered in Admin Audit Log Allows Session Hijacking May 28, 2026
  • CVE-2026-40905 LinkAce: Password Reset Poisoning via X-Forwarded-Host Header Injection Leading to Account Takeover Apr 21, 2026
  • CVE-2026-35516 LinkAce has SSRF via CheckLinksCommand - Link URL Update Bypasses laravel-html-meta Protection Apr 7, 2026
  • CVE-2026-33953 LinkAce's SSRF protection can be bypassed via internal hostname resolution in LinkAce Mar 27, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-27458 is "LinkAce: Stored XSS in Atom Feed via CDATA Escape in List Description", rated Medium. It affects LinkAce (Kovah); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.4 describes technical severity. EPSS 0.26% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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