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The Eclipse Foundation Eclipse Jetty

MonitorNot in CISA KEVCVE-2018-12538CWE-6

Not confirmed exploited. 1 of 8 rule sources name it.

Edge rules
1/8
Our test
No exploit yet
CVSS
—
EPSS
2.6% Top 15%
Posts, 14d
02026-10-22: 0 posts2026-10-23: 0 posts2026-10-24: 0 posts2026-10-25: 0 posts2026-10-26: 0 posts2026-10-27: 0 posts2026-10-28: 0 posts2026-10-29: 0 posts2026-10-30: 0 posts2026-10-31: 0 posts2026-11-01: 0 posts2026-11-02: 0 posts2026-11-03: 0 posts2026-11-04: 0 posts
Published
2018-06-22
In Eclipse Jetty versions 9.4.0 through 9.4.8, when using the optional Jetty provided FileSessionDataStore for persistent storage of HttpSession details, it is possible for a malicious user to access/hijack other HttpSessions and even… More

In Eclipse Jetty versions 9.4.0 through 9.4.8, when using the optional Jetty provided FileSessionDataStore for persistent storage of HttpSession details, it is possible for a malicious user to access/hijack other HttpSessions and even delete unmatched HttpSessions present in the FileSystem's storage for the FileSessionDataStore.

MonitorLast checked 2026-11-03

The risk

Exploitation in the wild is not established by CISA KEV.

Who is affected

Teams running The Eclipse Foundation Eclipse Jetty (before 9.4.9; 9.4.0 to before unspecified).

Next steps

  1. Apply the vendor's fix; the advisory lists the affected and fixed versions.
  2. Keep a WAF rule in place while you patch: F5 ships a rule you may need to switch on. A WAF rule reduces exposure; it does not replace the patch. Edge coverage
  3. Check which WAF sits in front of your site and whether it covers this CVE. Check your domain

Attack traffic on Cloudflare

Cloudflare Radar
  • Rules for named CVEs5.9% of mitigated layer 7 attacks, 7 days2026-10-06: 0.6%2026-10-07: 1.8%2026-10-08: 3%2026-10-09: 6.3%2026-10-10: 1.9%2026-10-11: 0.8%2026-10-12: 0.6%2026-10-13: 0.6%2026-10-14: 4.2%2026-10-15: 2.3%2026-10-16: 1.3%2026-10-17: 1.6%2026-10-18: 1.1%2026-10-19: 3.2%2026-10-20: 4.7%2026-10-21: 5.7%2026-10-22: 5.5%2026-10-23: 9.8%2026-10-24: 7%2026-10-25: 5%2026-10-26: 7.3%2026-10-27: 8.1%2026-10-28: 10.1%2026-10-29: 0.9%2026-10-30: 4.1%2026-10-31: 7.5%2026-11-01: 8.7%2026-11-02: 2.4%2026-11-03: 9.1%

Radar groups Cloudflare's WAF managed rules by category; it does not publish counts per CVE. These shares show how much attack traffic targets this kind of flaw across Cloudflare's network (28-day trend). They are not compromised systems, and seeing few attempts on Cloudflare does not prove an absence elsewhere. Radar data as of 2026-11-03. Radar ↗

Check your exposure with an agent

Read-only

Copy this into an agent with access to your infrastructure. It asks for an evidence-based, read-only assessment: affected systems, exposure, compensating controls and what is still unknown. It does not scan or change anything by itself.

Prompt12 lines
Assess whether the infrastructure available to you is affected by CVE-2018-12538 (The Eclipse Foundation Eclipse Jetty). Perform a read-only assessment within your authorized access. Do not send exploit traffic, scan third-party systems, change configuration or restart services.

1. Verify the CVE record at https://www.cve.org/CVERecord?id=CVE-2018-12538 and the vendor advisory. Establish affected and fixed versions, including vendor backports. The record lists: The Eclipse Foundation Eclipse Jetty: affected before 9.4.9; 9.4.0 to before unspecified. Cite sources and retrieval dates; flag anything you cannot verify.
2. Inventory deployments of The Eclipse Foundation Eclipse Jetty: asset, environment, owner where known, installed version or build, and how you confirmed it (package metadata, a version endpoint, image tags). An image tag alone does not prove the running version.
3. Identify which deployments are reachable from the internet or untrusted networks, and through which paths (direct origin, load balancer, CDN or WAF).
4. Assess compensating controls separately from patch status. Current edge WAF coverage for this CVE: F5: rule exists, check whether it is enabled. Live data: https://cve.vigilbase.com/api/v1/cves/CVE-2018-12538. Check whether the rule is enabled and in block mode on each path, and whether any path bypasses the WAF. A WAF rule is not a patch.
5. Check logs on exposed instances for requests matching the public exploit, if your access allows.

Return a short summary and a table: asset | version/build | assessment (affected, fixed, not applicable, unknown) | exposure | compensating control | evidence | next action. List what you could not assess and the access needed to resolve it. Do not infer absence of compromise from patch status or a lack of alerts.

Remediation guidance: Apply the vendor's fix; the advisory lists the affected and fixed versions. Keep a WAF rule in place while you patch: F5 ships a rule you may need to switch on. A WAF rule reduces exposure; it does not replace the patch.
More: https://cve.vigilbase.com/cve/CVE-2018-12538

Sources

Cited
CVE record

No CVSS score in the record. Weakness: CWE-6.

CVE-2018-12538 ↗NVD ↗

Exploit evidence

No public exploit code found in Exploit-DB, Metasploit, nuclei-templates or GitHub. That does not mean none exists.

CISA KEV

Not in the KEV catalog (catalog 2026.11.03, checked 2026-11-04). Absence from KEV is not evidence that it cannot be exploited.

CISA KEV catalog ↗

EPSS

2.56% probability of exploitation activity in the next 30 days, higher than 85% of CVEs (2026-11-02).

FIRST EPSS ↗

WAF vendor statements

F5 names it in a changelog. Quotes and dates below.

Vendor statements

Ask Vigil

AI · answers from this page
Ask about CVE-2018-12538: who's covered, what to patch first, how vendors compare. I cite sources and won't help with attacks.

Public exploits

None found
0 Metasploit0 Exploit-DB0 Scanner template0 GitHub PoCs

No exploit in Exploit-DB or Metasploit, and no scanner template. That lowers, but doesn't remove, the chance of mass exploitation.

Timeline

  1. 2018-06-22
    CVE published
    CVE List
  2. 2023-08-08
    F5 rule names it
    Earliest entry we can see is an update

Social

2026-10-22: 0 posts2026-10-23: 0 posts2026-10-24: 0 posts2026-10-25: 0 posts2026-10-26: 0 posts2026-10-27: 0 posts2026-10-28: 0 posts2026-10-29: 0 posts2026-10-30: 0 posts2026-10-31: 0 posts2026-11-01: 0 posts2026-11-02: 0 posts2026-11-03: 0 posts2026-11-04: 0 posts

No posts seen yet on X, Bluesky, Mastodon, Hacker News or GitHub.

Vendor statements

Quoted
CloudflareWAF Managed RulesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

AWSAWS WAF Managed RulesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

Microsoft AzureFront Door and Application Gateway WAF (DRS)No public claim

We found no public statement from this vendor naming this CVE. That is not proof of no protection: generic rules may still catch it. The rule tables name CVEs but carry no dates, so Azure is left out of every time-to-rule figure.

Google CloudCloud Armor preconfigured WAF rulesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

FastlyNext-Gen WAF virtual patchesBefore feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.

F5Attack signatures (Distributed Cloud WAF)1 quoteRule published

Named by 2023-08-08; the first entry is an update, so the rule may be older.

2023-08-08Updated200020003Source
Updated: signature 200020003 "Jetty FileBasedSessionStore Session Stealing" (Session Hijacking, risk Medium), systems: Jetty. References: CVE-2018-12538.
AkamaiApp & API Protector (Adaptive Security Engine)No public source

This vendor publishes no machine-readable rule changelog we can check.

OWASP CRSCore Rule Set (open source, used inside many WAFs)Before feed history

The CVE predates the oldest entry in this vendor's public feed, so a rule may exist that we cannot see.