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Attackers have exploited a server-side request forgery (SSRF) vulnerability in the Pandoc Linux utility, identified as CVE-2025-51591, to target the Amazon Web Services (AWS) Instance Metadata Service (IMDS) and steal EC2 IAM credentials. The flaw, which has a CVSS score of 6.5, allows threat actors to inject specially crafted HTML iframe elements into Pandoc, enabling them to direct requests to the IMDS endpoint. By leveraging this SSRF vulnerability, attackers can harvest temporary AWS credentials from EC2 instances without requiring direct host access, such as remote code execution or path traversal. The IMDS is a critical AWS component that provides metadata and temporary credentials to applications running on EC2 instances, facilitating secure interactions with other AWS services like S3, RDS, and DynamoDB. The exploitation method involves submitting HTML documents with malicious iframe elements, which, if processed by a vulnerable Pandoc instance on an EC2 host, can access sensitive metadata paths and extract credentials. Security researchers from Wiz highlighted that enforcing IMDSv2, which requires session-based authentication, can effectively block such attacks, as was observed in incidents where IMDSv2 was enabled. Organizations are advised to mitigate this risk by using Pandoc's '-f html+raw_html' or '--sandbox' options and by ensuring IMDSv2 is enforced across all EC2 environments. The attacks underscore the broader risk posed by SSRF vulnerabilities in cloud environments, as they can lead to severe consequences such as network reconnaissance and cloud credential compromise. Resecurity researchers have warned that SSRF flaws, when combined with access to IMDS, can have far-reaching impacts on cloud security. The incident demonstrates that attackers are actively searching for SSRF vulnerabilities in web applications running on EC2 instances to gain unauthorized access to AWS resources. The exploitation of CVE-2025-51591 is not merely theoretical; it has been observed in the wild, with real-world attempts to compromise cloud infrastructure. The incident also highlights the importance of secure application design and the need for defense-in-depth strategies in cloud environments. Security teams are urged to review their use of Pandoc and similar utilities, especially in cloud-hosted environments, to ensure they are not inadvertently exposing sensitive metadata endpoints. The case further illustrates the evolving tactics of threat actors targeting cloud infrastructure through application-layer vulnerabilities. Cloud providers and customers alike must remain vigilant and proactive in patching and securing their environments against such emerging threats. The incident serves as a reminder that even medium-severity vulnerabilities can have significant impact when exploited in the right context. Finally, the coordinated disclosure and analysis by security firms like Wiz have been instrumental in raising awareness and driving mitigation efforts for this vulnerability.
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Security reporting detailed that exploitation of CVE-2025-51591 could be blocked by enforcing AWS IMDSv2 and by using safer Pandoc options. The disclosure highlighted the broader risks of SSRF, including cloud credential theft and internal network reconnaissance.
Threat actors actively exploited the Pandoc server-side request forgery vulnerability CVE-2025-51591 by submitting crafted HTML documents with iframes targeting the AWS Instance Metadata Service. The activity was aimed at retrieving EC2 IAM temporary credentials without requiring direct access to the host.
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AWS documented an incident-response scenario in which an attacker exploited a server-side request forgery (SSRF) flaw in an EC2-hosted web application to retrieve temporary credentials for the instance's attached `webdev` IAM role through IMDSv1. The attacker enumerated the role's permissions, established an AWS Management Console session without MFA, pivoted from `us-east-1` to `us-east-2`, and enumerated Amazon Bedrock foundation models. The actor then invoked Amazon Nova Pro through the Converse API, resulting in unauthorized token consumption. The activity was enabled by IMDSv1 exposure, an overprivileged EC2 role with unnecessary cross-Region Bedrock permissions, and missing MFA, with inconsistent regional logging and controls potentially limiting detection. AWS advises remediating the SSRF flaw, requiring IMDSv2 for EC2 metadata access, revoking and investigating use of the compromised role, reviewing CloudTrail across all Regions, restricting Bedrock permissions, and enabling Bedrock model-invocation logging to determine whether prompts or generated outputs were exposed.
Sep 5, 2026
Mandiant reported that **UNC2903** targeted public-facing web applications in AWS environments to steal temporary cloud credentials by abusing the Amazon **Instance Metadata Service (IMDS)**. The activity began in 2021 and relied on **server-side request forgery (SSRF)** in vulnerable applications, including **Adminer** affected by `CVE-2021-21311`, to query metadata endpoints and retrieve AWS credentials tied to the compromised instances. After obtaining credentials, the threat actor attempted access to **S3 buckets** and other AWS resources in what Mandiant described as a multi-phase intrusion chain involving internet scanning, reconnaissance, exploit attempts, and manual validation before credential abuse and data theft. The report said environments still using **IMDSv1** were especially exposed, while **IMDSv2** and **GuardDuty** offer stronger defenses, and warned that similar metadata-service abuse could affect other cloud platforms with comparable features.
Jun 29, 2026
A critical vulnerability in the Axios HTTP client library, tracked as **`CVE-2026-40175`**, allows attackers to turn polluted JavaScript object properties into malicious HTTP headers and abuse outbound requests for **SSRF**, **request smuggling**, and potential **remote code execution**. Researchers said the flaw stems from improper header handling in Axios’s HTTP adapter and unsafe config merging, which can let `Object.prototype` values containing CRLF characters be injected into requests. The issue can be chained with prototype pollution in other npm packages to target internal services, including the AWS EC2 metadata endpoint at `169.254.169.254`, potentially bypassing **IMDSv2** and exposing cloud credentials or broader infrastructure. A public proof-of-concept was released alongside disclosure, raising urgency for defenders even though active exploitation had not been confirmed at the time of reporting. The flaw affects Axios versions before **`1.13.2`**, while maintainers said **`1.15.0`** introduces strict header validation that blocks CRLF-based header injection; organizations were urged to upgrade and audit dependencies such as **`body-parser`**, **`qs`**, and **`minimist`** for prototype pollution paths. One report cited internet-wide estimates of more than **48,000** potentially exposed instances, underscoring the risk of unauthorized internal access and possible full cloud compromise.
Jun 29, 2026