VulnerabilityPublished 27 Apr 2026Updated 15 Jul 2026

CVE-2026-40975: Spring Boot · Weak Randomness

Affects Spring BootSource CVE Database V5

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Not known to be exploited · CVSS 4.8 Medium · fixed in 4.0.6 : update Spring Boot when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

4.8Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.3% chance of exploitation in 30 days – higher than 24% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0.6, 3.5.14, 3.4.16 +2

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Attack Vector: Network
Attack Complexity: High
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: High: A successful attack depends on conditions beyond the attacker's control. That is, a successful attack cannot be accomplished at will, but requires the attacker to invest in some measurable amount of effort in preparation or execution against the vulnerable component before a successful attack can be expected. For example, a successful attack may require an attacker to: gather knowledge about the environment in which the vulnerable target/component exists; prepare the target environment to improve exploit reliability; or inject themselves into the logical network path between the target and the resource requested by the victim in order to read and/or modify network communications (e.g., a man in the middle attack).
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Apr 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
SpringSpring Boot	Affected >=4.0.0 <4.0.6	Fixed in 4.0.6
SpringSpring Boot	Affected >=3.5.0 <3.5.14	Fixed in 3.5.14
SpringSpring Boot	Affected >=3.4.0 <3.4.16	Fixed in 3.4.16
SpringSpring Boot	Affected >=3.3.0 <3.3.19	Fixed in 3.3.19
SpringSpring Boot	Affected >=2.7.0 <2.7.33	Fixed in 2.7.33
Mavenorg.springframework.boot/spring-boot`pkg:maven/org.springframework.boot/spring-boot`Other threats	Affected 2.7.0 – 4.0.0 5 affected builds	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Fixed versions of Spring Boot are available and should be applied: 2.7.33, 3.3.19, 3.4.16, 3.5.14, and 4.0.6 or later. Users should avoid using ${random.value}, ${random.int}, and ${random.long} for generating secrets and instead use ${random.uuid} or other cryptographically secure random generators. Refer to the Red Hat advisories for detailed patch information and update instructions. Patch status is confirmed by vendor advisories. No additional mitigation is required beyond applying the official fixes and avoiding insecure random value usage for secrets.

Description

Values produced by ${random.value} are not suitable for use as secrets. ${random.uuid} is not affected. ${random.int} and ${random.long} should never be used for secrets as they are numeric values with a predictable range. Affected: Spring Boot 4.0.0–4.0.5 (fix 4.0.6), 3.5.0–3.5.13 (fix 3.5.14), 3.4.0–3.4.15 (fix 3.4.16), 3.3.0–3.3.18 (fix 3.3.19), 2.7.0–2.7.32 (fix 2.7.33); random value property source / weak PRNG for secrets. Versions that are no longer supported are also affected per vendor advisory.

Impact

The vulnerability allows the generation of secrets using insufficiently random values, which can lead to information disclosure or compromise of secret-based security mechanisms. The impact is limited to confidentiality and integrity with low severity, as indicated by the CVSS score of 4.8. There is no impact on availability. Exploitation could potentially allow attackers to predict or guess secrets generated by the affected random value property source, weakening security controls that rely on these secrets.

CWE-330Use of Insufficiently Random Values (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses insufficiently random numbers or values in a security context that depends on unpredictable numbers.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
Architecture and Design
Use a well-vetted algorithm that is currently considered to be strong by experts in the field, and select well-tested implementations with adequate length seeds.
Implementation
Consider a PRNG that re-seeds itself as needed from high quality pseudo-random output sources, such as hardware devices.
Architecture and Design · Requirements · Libraries or Frameworks
Use products or modules that conform to FIPS 140-2 to avoid obvious entropy problems. Consult FIPS 140-2 Annex C ("Approved Random Number Generators").
OWASP Cheat Sheets
Forgot Password (opens in a new tab)
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
OWASP ASVS 4.0.3
V2.3.1 (opens in a new tab)
V2.6.2 (opens in a new tab)
V2.7.6 (opens in a new tab)
Attack patterns
Signature Spoofing by Key Recreation (opens in a new tab)
Session Credential Falsification through Prediction (opens in a new tab)
Brute Force (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).
CWE-338Use of Cryptographically Weak Pseudo-Random Number Generator (PRNG) (opens in a new tab)
Base weaknessLikelihood of exploit: MediumOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a Pseudo-Random Number Generator (PRNG) in a security context, but the PRNG's algorithm is not cryptographically strong.
Implementation
Use functions or hardware which use a hardware-based random number generation for all crypto. This is the recommended solution. Use CyptGenRandom on Windows, or hw_rand() on Linux.
OWASP Cheat Sheets
Transport Layer Protection (opens in a new tab)
User Privacy Protection (opens in a new tab)
Password Storage (opens in a new tab)
Cryptographic Storage (opens in a new tab)
HSTS (opens in a new tab)
OWASP ASVS 4.0.3
V6.3.3 (opens in a new tab)
V6.3.2 (opens in a new tab)
V6.3.1 (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 15 Jul 2026, 09:12 UTC

WeaknessesCWE-330, CWE-338

Technical details

References

Community reviews

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