Inbound WS-Security allows RSA PKCS#1 v1.5 key transport by default

published 2026-06-11 4 mo ago modified 2026-09-04 2 mo ago also GHSA-p7qj-2q5w-f9r7 , EUVD-2026-36206

cvss: 4.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.1%; EPSS 0.1% chance of exploitation in 30 days, percentile 2%
public exploits: 0; none known

Wss4jSecurityInterceptor defaulted allowRSA15KeyTransportAlgorithm to true, overriding Apache WSS4J's safer default for validation RequestData. Inbound WS-Security decryption could therefore accept RSA PKCS#1 v1.5 (rsa-1_5) encrypted key material unless operators explicitly reconfigured the flag.

Affected versions: Spring Web Services 5.0.0 through 5.0.1; 4.1.0 through 4.1.3; 4.0.0 through 4.0.18; 3.1.0 through 3.1.8.

Patch / fix

fixed in 2

maven org.springframework.ws:spring-ws-security 4.1.4, 5.0.2
Spring Spring Web Services 3.1.9, 4.0.19, 4.1.3.1, 5.0.1.1

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 4 mo ago (2026-06-11)

Exploit prediction

0.13% chance of exploitation in the next 30 days, higher than 2% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
GitHub	3.1	4.8	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
maven	org.springframework.ws:spring-ws-security	>=5.0.0, <5.0.2 >=4.1.0, <4.1.4 >=4.0.0, <=4.0.18 >=3.1.0, <=3.1.8	5.0.2 4.1.4

Affected products

Spring Spring Web Services

Classification

Weakness

CWE-327 Use of a Broken or Risky Cryptographic Algorithm

References

spring.io /security/cve-2026-40996
web, vendor-advisory, mitigation
nvd.nist.gov /vuln/detail/CVE-2026-40996
advisory
github.com /spring-projects/spring-ws
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary