CVE-2025-14764VulnerabilityPublished 17 Dec 2025

CVE-2025-14764: AWS S3 Encryption Client for Go · Weak Cryptography

Affects AWS S3 Encryption Client for GoSource CVE Database V5

Not known to be exploited · CVSS 5.3 Medium : upgrade to 4.0 when convenient.

Data as of 25 Oct 2026, 19:02 UTC

CVSS 3.1 base score

5.3Medium

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

EPSS: 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0

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

Attack Vector: Network
Attack Complexity: High
Privileges Required: Low
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
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: Low: The attacker is authorized with (i.e., requires) privileges that provide basic user capabilities that could normally affect only settings and files owned by a user. Alternatively, an attacker with Low privileges may have the ability to cause an impact only to non-sensitive resources.
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: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to 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 17 Dec 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 2026-10-25.

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.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC 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 github.com/aws/amazon-s3-encryption-client-go to 4.0.

Affected software

Product	Affected	Fixed in
Gogithub.com/aws/amazon-s3-encryption-client-go`pkg:golang/github.com/aws/amazon-s3-encryption-client-go`Other threats	Affected <4.0	Fixed in 4.0

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

AI-suggested

European organizations should immediately upgrade the Amazon S3 Encryption Client for Go to version 4.0 or later to ensure cryptographic key commitment is properly implemented. Review and audit S3 bucket permissions to minimize write access, especially for users or services that do not require it, employing the principle of least privilege. Avoid storing encrypted data keys in instruction files where possible; prefer embedding EDKs in S3 metadata records as recommended by AWS best practices. Implement monitoring and alerting for unusual write activities or modifications to instruction files within S3 buckets. Conduct integrity checks and validation of decrypted data where feasible to detect tampering early. Incorporate cryptographic best practices and regularly update encryption libraries to stay protected against emerging vulnerabilities. Additionally, document and test incident response procedures for potential data integrity incidents related to cloud storage. Engage with AWS support or security advisories for ongoing updates and patches related to this vulnerability. Finally, ensure compliance teams are aware of the risk to address regulatory implications proactively.

Description

CVE-2025-14764 is a medium-severity vulnerability in the Amazon S3 Encryption Client for Go involving the use of a broken or risky cryptographic algorithm due to missing cryptographic key commitment. This flaw allows a user with write access to an S3 bucket to introduce a new encrypted data key (EDK) that decrypts to different plaintext when the encrypted data key is stored in an instruction file rather than S3 metadata. The vulnerability does not impact confidentiality but can compromise data integrity by enabling unauthorized data manipulation. Exploitation requires network access, low privileges (write access), and no user interaction, with a CVSS score of 5.3. AWS has addressed this issue in version 4.0 or later of the S3 Encryption Client for Go. European organizations using vulnerable versions should upgrade promptly to prevent potential data integrity attacks, especially those relying on instruction file storage for encrypted data keys. Countries with significant AWS usage and cloud adoption, such as Germany, the UK, France, and the Netherlands, are most likely to be affected.

Impact

For European organizations, this vulnerability primarily threatens data integrity within cloud storage environments using the vulnerable AWS S3 Encryption Client for Go. Attackers with write access to S3 buckets could manipulate encrypted data keys to cause decryption to altered plaintext, potentially corrupting critical data or injecting malicious content without detection. This undermines trust in encrypted data and can disrupt business operations relying on data accuracy, such as financial records, healthcare information, or intellectual property. Although confidentiality is not directly impacted, the integrity breach can lead to compliance violations under GDPR and other data protection regulations, especially if altered data leads to incorrect decisions or disclosures. The medium severity and requirement for write access limit the attack surface but do not eliminate risk, particularly in multi-tenant or shared environments where write permissions may be more broadly granted. Organizations with automated data processing pipelines or compliance auditing relying on encrypted data integrity are especially vulnerable. The absence of known exploits provides a window for proactive mitigation, but the risk remains significant given the potential for stealthy data tampering.

CWE-327Use of a Broken or Risky Cryptographic Algorithm (opens in a new tab)
Class weaknessLikelihood of exploit: HighOWASP Top 10 A04:2025: Cryptographic Failures (opens in a new tab)
The product uses a broken or risky cryptographic algorithm or protocol.
Architecture and Design · Libraries or Frameworks
When there is a need to store or transmit sensitive data, use strong, up-to-date cryptographic algorithms to encrypt that data. Select a well-vetted algorithm that is currently considered to be strong by experts in the field, and use well-tested implementations.
Architecture and Design
Ensure that the design allows one cryptographic algorithm to be replaced with another in the next generation or version. Where possible, use wrappers to make the interfaces uniform. This will make it easier to upgrade to stronger algorithms.
Architecture and Design
Carefully manage and protect cryptographic keys (see CWE-320). If the keys can be guessed or stolen, then the strength of the cryptography itself is irrelevant.
OWASP Cheat Sheets
Cryptographic Storage (opens in a new tab)
Key Management (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)
OWASP ASVS 4.0.3
V8.3.7 (opens in a new tab)
V2.9.3 (opens in a new tab)
V6.2.2 (opens in a new tab)
Attack patterns
Encryption Brute Forcing (opens in a new tab)
Creating a Rogue Certification Authority Certificate (opens in a new tab)
Signature Spoof (opens in a new tab)
Signature Spoofing by Improper Validation (opens in a new tab)
Cryptanalysis of Cellular Encryption (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 24 Dec 2025, 21:59 UTC

WeaknessesCWE-327

Technical details

References

Community reviews

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