CVE Intelligence
Medium Cross-site scripting

CVE-2018-0499 — xapian-core Cross-site Scripting vulnerability

A cross-site scripting vulnerability in queryparser/termgenerator_internal.cc in Xapian xapian-core before 1.4.6 exists due to incomplete HTML escaping by Xapian::MSet::snippet().

Published Jul 2, 2018 · Updated Oct 18, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP, GitHub Security Advisories · CNA: debian

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 1% (30-day exploitation probability)+10
  • Technical severity (medium)+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
1.04%
ahead of 64% of scored CVEs · Oct 19, 2026
Affects
Canonical
Ubuntu Linux and 1 more
CVSS base
6.1
Medium · 2 source(s)

Remediation

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

  • Documented patch — trac.xapian.org (NIST National Vulnerability Database)
  • Rubygems Xapian-core: fixed in version 1.4.6 — github.com (GitHub Security Advisories)

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 (Canonical Ubuntu Linux, Xapian Xapian-core, Rubygems Xapian-core).
  2. The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
  3. Apply the fixed version or the patch documented under Remediation.
  4. Exploitation requires user interaction: tighten email/web filtering and warn affected users.
  5. Search available logs for exploit probes matching the vulnerability class (cross-site scripting), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Canonical Ubuntu Linux version 17.10version 18.04 Vulnerable NIST National Vulnerability Database
Xapian Xapian-core < 1.4.6 Vulnerable NIST National Vulnerability Database
Rubygems Xapian-core < 1.4.6 Vulnerable GitHub Security Advisories

Attack characteristics

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

Attack vector
Network
Attack complexity
Low
Privileges required
None
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
6.1 CVSS 3.0 Medium 2.8 2.7 nvd@nist.gov via NIST National Vulnerability Database
6.1 CVSS 3.0 Medium — — GitHub, Inc. via GitHub Security Advisories
4.3 CVSS 2.0 Medium 8.6 2.9 nvd@nist.gov via NIST National Vulnerability Database
CVSS:3.0/AV:N/AC:L/PR:N/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-79 · Cross-site Scripting (XSS)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 18, 2026 → Oct 19, 2026 · 2 reading(s) · max 1.04%

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).
  • Monitor CSP violation reports and script payloads in reflected parameters.
web/proxy/WAF logsnetwork IDS/IPSapplication logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Fix documented
    Oct 18, 2026 · GitHub Security Advisories
  • Affected products added · rubygems/xapian-core
    Oct 18, 2026 · GitHub Security Advisories
  • Record published
    Oct 18, 2026
  • Fix documented
    Oct 18, 2026 · NIST National Vulnerability Database
  • Affected products added · xapian/xapian-core, canonical/ubuntu linux
    Oct 18, 2026 · NIST National Vulnerability Database
  • CVSS changed · 6.1
    Oct 18, 2026 · NIST National Vulnerability Database
  • Source status changed · → Modified
    Oct 18, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 18, 2026 · Alertas do Telegram
  • 2018
  • CVE published
    Jul 2, 2018 · debian

Source activity

Repeated readings are counted rather than listed.

  • 2× References added · Oct 18, 2026 – Oct 18, 2026
  • 1× Official description updated · Oct 18, 2026 – Oct 18, 2026

References

6 on the record

Elsewhere on this site

Canonical
every CVE for this vendor
Cross-site scripting
same class
CWE-79
other pages naming this weakness

Related CVEs (same products)

  • CVE-2026-77643 A cross-site scripting vulnerability in queryparser/termgenerator_internal.cc in Xapian xapian... Aug 20, 2026
  • CVE-2026-47333 Out-of-bounds read in Ubuntu Linux AppArmor notification handling May 28, 2026
  • CVE-2026-47337 NULL pointer dereference in Ubuntu Linux AppArmor IPv4/IPv6 socket mediation May 28, 2026
  • CVE-2026-47334 Deadlock or kernel panic in Ubuntu Linux AppArmor notification handling May 28, 2026
  • CVE-2026-47335 NULL pointer dereference in Ubuntu Linux AppArmor notification handling May 28, 2026
  • CVE-2026-47336 Use of uninitialized value in Ubuntu Linux AppArmor IPv4/IPv6 socket mediation rules May 28, 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 CISA SSVC assessment.
  • 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-2018-0499 is "xapian-core Cross-site Scripting vulnerability", rated Medium. It affects Ubuntu Linux (Canonical); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.1 describes technical severity. EPSS 1.04% 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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