CVE-2019-17563 — Session Fixation in Apache Software Foundation Tomcat

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)
• 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.

1. Identify exposed assets running the affected vendor/product/version combinations (Apache Software Foundation Tomcat, Canonical Ubuntu Linux, Debian Debian Linux…).
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. EPSS ahead of 96% of scored CVEs: prioritize it in the patch queue.
6. Search available logs for exploit probes matching the vulnerability class (authentication), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

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.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-384 · Session Fixation

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 10.69%

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).
• Review authentication logs: logins without MFA, anomalous sessions and recently created accounts.

Timeline

What happened to this CVE, newest first.

• 2026
• Affected products added · apache software foundation/apache tomcat
  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 · 7.5
  Oct 13, 2026 · NIST National Vulnerability Database
• Source status changed · → Modified
  Oct 13, 2026 · NIST National Vulnerability Database
• Record created in this database
  Oct 13, 2026 · NIST National Vulnerability Database
• 2019
• CVE published
  Dec 23, 2019 · apache

Source activity

Repeated readings are counted rather than listed.

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

References

19 on the record

• lists.apache.org/thread.html/8b4c1db8300117b28a0f3f743c0b9e3f964687a690cdf9662a884bbd%
  Mailing List, Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpuapr2020.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpujul2020.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• www.oracle.com/security-alerts/cpujan2021.html
  Patch, Third Party Advisory, x_refsource_MISC, NIST National Vulnerability Database
• lists.debian.org/debian-lts-announce/2020/01/msg00024.html
  Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/r48c1444845fe15a823e1374674bfc297d5008a5453788099ea14caf0
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• www.debian.org/security/2019/dsa-4596
  Third Party Advisory, vendor-advisory, x_refsource_DEBIAN, NIST National Vulnerability Database
• lists.apache.org/thread.html/reb9a66f176df29b9a832caa95ebd9ffa3284e8f4922ec4fa3ad8eb2e
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/raba0fabaf4d56d4325ab2aca8814f0b30a237ab83d8106b115ee279a
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• security.netapp.com/advisory/ntap-20200107-0001/
  Third Party Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
• usn.ubuntu.com/4251-1/
  Third Party Advisory, vendor-advisory, x_refsource_UBUNTU, NIST National Vulnerability Database
• lists.debian.org/debian-lts-announce/2020/05/msg00026.html
  Mailing List, Third Party Advisory, mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/r6ccee4e849bc77df0840c7f853f6bd09d426f6741247da2b7429d5d9
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• seclists.org/bugtraq/2019/Dec/43
  Mailing List, Third Party Advisory, mailing-list, x_refsource_BUGTRAQ, NIST National Vulnerability Database
• security.gentoo.org/glsa/202003-43
  Third Party Advisory, vendor-advisory, x_refsource_GENTOO, NIST National Vulnerability Database
• lists.apache.org/thread.html/r3bbb800a816d0a51eccc5a228c58736960a9fffafa581a225834d97d
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.apache.org/thread.html/r9136ff5b13e4f1941360b5a309efee2c114a14855578c3a2cbe5d19c
  mailing-list, x_refsource_MLIST, NIST National Vulnerability Database
• lists.opensuse.org/opensuse-security-announce/2020-01/msg00013.html
  Third Party Advisory, vendor-advisory, x_refsource_SUSE, NIST National Vulnerability Database
• www.debian.org/security/2020/dsa-4680
  Third Party Advisory, vendor-advisory, x_refsource_DEBIAN, NIST National Vulnerability Database

Elsewhere on this site

Related CVEs (same products)

• High CVE-2026-12996 A use-after-free in OpenVPN 2.6.0 through 2.6.20 and 2.7_alpha1 through 2.7.4 allows remote... Jul 30, 2026
• Critical CVE-2026-55276 Apache Tomcat: Logged effective web.xml is incomplete Jun 29, 2026
• Medium CVE-2026-55956 Apache Tomcat: Security constraints for default servlet ignored method Jun 29, 2026
• High CVE-2026-55957 Apache Tomcat: Authentication bypass with JNDIRealm and GSSAPI authenticated bind Jun 29, 2026
• Medium CVE-2026-55955 Apache Tomcat: EncryptInterceptor not protected against replay attacks Jun 29, 2026
• Medium CVE-2026-50229 Apache Tomcat: XSS in number guess example Jun 29, 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-2019-17563 is "Session Fixation in Apache Software Foundation Tomcat", rated High. 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 7.5 describes technical severity. EPSS 10.69% 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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