CVE-2026-41727 — In Spring for Apache Kafka, forged retry topic headers subvert retry routing and backoff behavior
Spring Kafka's retry topic infrastructure did not sufficiently validate user-controlled header values before acting on them. A producer could send a record with a crafted retry_topic-attempts header to supply an out-of-range attempt count and cause the retry topic router to misidentify where the message was in the retry sequence. Affected versions: Spring for Apache Kafka 4.0.0 through 4.0.5; 3.3.0 through 3.3.15; 3.2.0 through 3.2.13; 2.9.0 through 2.9.13; 2.8.0 through 2.8.11.
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 0.4% (30-day exploitation probability)+5
- 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.
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.
No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.
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 (Spring Spring for Apache Kafka, Vmware Spring For Apache Kafka).
- No fix documented in the sources: reduce exposure and monitor the vendor advisory.
- Search available logs for exploit probes matching the vulnerability class (input validation), errors and authentication anomalies.
Affected scope
Vendor, product and versions as the sources word them.
| Vendor | Product | Versions | Status | Source |
|---|---|---|---|---|
| Spring | Spring for Apache Kafka | ≥ 4.0.0 and < 4.0.5.1≥ 3.3.0 and < 3.3.15.1≥ 3.2.0 and < 3.2.14≥ 2.9.0 and < 2.9.14≥ 2.8.0 and < 2.8.12 | Vulnerable | CVE Program (cve.org) e CISA ADP |
| Vmware | Spring For Apache Kafka | ≥ 2.8.0 and < 2.8.12≥ 2.9.0 and < 2.9.14≥ 3.2.0 and < 3.2.14≥ 3.3.0 and < 3.3.15.1≥ 4.0.0 and < 4.0.5.1 | 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 |
|---|---|---|---|---|---|
| 6.5 | CVSS 3.1 | Medium | 2.8 | 3.6 | security@vmware.com via NIST National Vulnerability Database |
| 6.5 | CVSS 3.1 | Medium | — | — | vmware via CVE Program (cve.org) e CISA ADP |
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H (score shown at the top: security@vmware.com) Weakness MITRE
Weakness class according to MITRE’s CWE catalog.
EPSS over time FIRST
Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.42%
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).
Timeline
What happened to this CVE, newest first.
- 2026
- Affected products added · spring/spring for apache kafka
- SSVC assessment updated
- Record published
- CVSS changed · 6.5
- Source status changed · → Analyzed
- Record created in this database
- CVE published
Source activity
Repeated readings are counted rather than listed.
- 1× Official description updated · Oct 13, 2026 – Oct 13, 2026
References
1 on the record
Elsewhere on this site
Related CVEs (same products)
- Medium CVE-2026-59317 In Spring for Apache Kafka, missing header validation in DeadLetterPublishingRecovererFactory enables denial of service via a poison-pill loop Aug 27, 2026
- Medium CVE-2026-59278 In Spring for Apache Kafka, SSRF via DNS resolution triggered by untrusted java.net types in header mapper default trusted packages Aug 27, 2026
- Medium CVE-2026-41726 In Spring for Apache Kafka, unbounded delegate cache keyed on user-controlled, potentially malicious selector header Jun 9, 2026
- High CVE-2026-41731 In Spring for Apache Kafka, overly broad trusted-package matching in header mappers exposes JDK classes to deserialization Jun 9, 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 fixed version, patch or mitigation documented.
- 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-2026-41727 is "In Spring for Apache Kafka, forged retry topic headers subvert retry routing and backoff behavior", rated Medium. It affects Spring for Apache Kafka (Spring); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.5 describes technical severity. EPSS 0.42% 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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