CVE-2016-0762 — Observable Discrepancy in Apache Software Foundation Tomcat
The Realm implementations in Apache Tomcat versions 9.0.0.M1 to 9.0.0.M9, 8.5.0 to 8.5.4, 8.0.0.RC1 to 8.0.36, 7.0.0 to 7.0.70 and 6.0.0 to 6.0.45 did not process the supplied password if the supplied user name did not exist. This made a timing attack possible to determine valid user names. Note that the default configuration includes the LockOutRealm which makes exploitation of this vulnerability harder.
Who exploits it and how urgent it is
A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.
How the score was calculated
- EPSS 8% (30-day exploitation probability)+14
- Technical severity (medium)+3
- 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.
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.
Remediation
Fixes and mitigations documented by the sources — linked to the original advisory.
- Documented patch — www.oracle.com (NIST National Vulnerability Database)
- Documented patch — www.oracle.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.
- Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Tomcat, Canonical Ubuntu Linux, Debian Debian Linux…).
- The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
- Apply the fixed version or the patch documented under Remediation.
- EPSS ahead of 95% of scored CVEs: prioritize it in the patch queue.
- Search available logs for exploit probes matching the vulnerability class (info disclosure), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Apache Software Foundation | Tomcat |
version 9.0.0-milestone6version 9.0.0-milestone1≥ 8.5.0 and ≤ 8.5.4≥ 8.0 and ≤ 8.0.36≥ 7.0.0 and ≤ 7.0.70≥ 6.0.0 and ≤ 6.0.45version 9.0.0-milestone2version 9.0.0-milestone3 and 5 moreversion 9.0.0-milestone4version 9.0.0-milestone5version 9.0.0-milestone7version 9.0.0-milestone8version 9.0.0-milestone9 |
Vulnerable | NIST National Vulnerability Database |
| Apache Software Foundation | Tomcat | version 9.0.0.M1 to 9.0.0.M9version 8.5.0 to 8.5.4version 8.0.0.RC1 to 8.0.36version 7.0.0 to 7.0.70version 6.0.0 to 6.0.45 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Canonical | Ubuntu Linux | version 16.04 | Vulnerable | NIST National Vulnerability Database |
| Debian | Debian Linux | version 8.0 | Vulnerable | NIST National Vulnerability Database |
| Netapp | Oncommand Insight | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Oncommand Shift | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Netapp | Snap Creator Framework | versions not specified by the source | Vulnerable | NIST National Vulnerability Database |
| Oracle | Communications Diameter Signaling Router | ≥ 8.0.0 and ≤ 8.5.0 | Vulnerable | NIST National Vulnerability Database |
| Oracle | Tekelec Platform Distribution | ≥ 7.4.0 and ≤ 7.7.1 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Desktop | version 7.0 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Eus | version 7.5version 7.4version 7.6version 7.7 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Server | version 7.0 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Server Aus | version 7.4version 7.6version 7.7 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Server Tus | version 7.6version 7.7 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Enterprise Linux Workstation | version 7.0 | Vulnerable | NIST National Vulnerability Database |
| Red Hat | Jboss Enterprise Web Server | version 3.0.0 | Vulnerable | NIST National Vulnerability Database |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Every base score collected
Sources score independently and may disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Scored by |
|---|---|---|---|---|---|
| 5.9 | CVSS 3.1 | Medium | 2.2 | 3.6 | nvd@nist.gov via NIST National Vulnerability Database |
| 4.3 | CVSS 2.0 | Medium | 8.6 | 2.9 | nvd@nist.gov via NIST National Vulnerability Database |
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N (score shown at the top: nvd@nist.gov) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 15, 2026 · 3 reading(s) · max 7.99%
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).
- Look for anomalous data read/export volumes and access to sensitive records.
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · apache software foundation/apache tomcat
- SSVC assessment updated
- Record published
- Fix documented
- CVSS changed · 5.9
- Source status changed · → Modified
- Record created in this database
- 2017
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
24 on the record
- www.oracle.com/security-alerts/cpuoct2021.html
- www.oracle.com//security-alerts/cpujul2021.html
- www.securityfocus.com/bid/93939
- lists.apache.org/thread.html/b5e3f51d28cd5d9b1809f56594f2cf63dcd6a90429e16ea9f83bbedc%
- lists.apache.org/thread.html/r587e50b86c1a96ee301f751d50294072d142fd6dc08a8987ae9f3a9b
- security.netapp.com/advisory/ntap-20180605-0001/
- lists.apache.org/thread.html/b8a1bf18155b552dcf9a928ba808cbadad84c236d85eab3033662cfb%
- lists.apache.org/thread.html/343558d982879bf88ec20dbf707f8c11255f8e219e81d45c4f8d0551%
- lists.apache.org/thread.html/1872f96bad43647832bdd84a408794cd06d9cbb557af63085ca10009%
- rhn.redhat.com/errata/RHSA-2017-0457.html
- lists.apache.org/thread.html/845312a10aabbe2c499fca94003881d2c79fc993d85f34c1f5c77424%
- www.debian.org/security/2016/dsa-3720
- lists.apache.org/thread.html/3d19773b4cf0377db62d1e9328bf9160bf1819f04f988315086931d7%
- lists.apache.org/thread.html/388a323769f1dff84c9ec905455aa73fbcb20338e3c7eb131457f708%
- usn.ubuntu.com/4557-1/
- lists.apache.org/thread.html/39ae1f0bd5867c15755a6f959b271ade1aea04ccdc3b2e639dcd903b%
- access.redhat.com/errata/RHSA-2017:2247
- lists.apache.org/thread.html/37220405a377c0182d2afdbc36461c4783b2930fbeae3a17f1333113%
- lists.apache.org/thread.html/r03c597a64de790ba42c167efacfa23300c3d6c9fe589ab87fe02859c
- lists.apache.org/thread.html/r9136ff5b13e4f1941360b5a309efee2c114a14855578c3a2cbe5d19c
- lists.apache.org/thread.html/b84ad1258a89de5c9c853c7f2d3ad77e5b8b2930be9e132d5cef6b95%
- access.redhat.com/errata/RHSA-2017:0455
- www.securitytracker.com/id/1037144
- access.redhat.com/errata/RHSA-2017:0456
Elsewhere on this site
Related CVEs (same products)
- High CVE-2026-87022 Apache Tomcat: WebSocket message smuggling with per-message-deflate 22d
- Critical CVE-2026-86350 Apache Tomcat: Regression in fix for CVE-2026-41293 can trigger request header mix-up 22d
- Critical CVE-2026-86248 Apache Tomcat: Fix for CVE-2026-34500 was incomplete. OCSP checks sometimes soft-fail with FFM even when soft-fail is disabled 22d
- High CVE-2026-78437 Apache Tomcat: HTTP/2 DoS via malformed request 22d
- High CVE-2026-78383 Apache Tomcat: AJP DoS via missing request body 22d
- High CVE-2026-79677 Apache Tomcat: WebSocket DoS due to lost asynchronous write timeout 22d
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-2016-0762 is "Observable Discrepancy in Apache Software Foundation Tomcat", rated Medium. It affects Tomcat (Apache Software Foundation); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 5.9 describes technical severity. EPSS 7.99% 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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