CVE-2025-21482 Overview
CVE-2025-21482 is a cryptographic weakness in Qualcomm firmware affecting the RSA PKCS padding decoding routine. The flaw spans hundreds of Qualcomm chipsets, including Snapdragon mobile, compute, automotive, IoT, wearable, and networking platforms. A local attacker with low privileges can exploit the weakness to compromise confidentiality and integrity of cryptographic operations. The issue is tracked under CWE-310 (Cryptographic Issues) and was disclosed in the Qualcomm Security Bulletin September 2025.
Critical Impact
A local, low-privileged attacker can leverage an improper RSA PKCS padding check to recover sensitive data or manipulate cryptographically protected material across a wide range of Qualcomm firmware.
Affected Products
- Qualcomm Snapdragon mobile platforms (including Snapdragon 4 Gen 1/2, 425–888+, 8cx, 8 Gen1 5G)
- Qualcomm modem and modem-RF systems (315 5G IoT, 9205/9206/9207 LTE, Snapdragon X5–X75 5G)
- Qualcomm compute, XR, automotive, wearable, IPQ networking, FastConnect, and WCN/WCD/WSA product lines
Discovery Timeline
- 2025-09-24 - CVE-2025-21482 published to NVD
- 2026-06-17 - Last updated in NVD database
Technical Details for CVE-2025-21482
Vulnerability Analysis
The vulnerability resides in the RSA PKCS #1 v1.5 padding decoding logic within affected Qualcomm firmware. During decryption or signature verification, the implementation fails to enforce padding checks in a manner that resists inference by a local caller. This weakness maps to CWE-310, covering cryptographic algorithm misuse. Because the affected code paths execute inside firmware for modems, security processors, wireless subsystems, and application platforms, exploitation can affect keys, tokens, and messages handled by trusted components. The attack requires local access and low privileges but no user interaction, and it does not impact availability.
Root Cause
The root cause is improper handling of PKCS #1 v1.5 padding during RSA decryption. Insufficient validation or non-uniform error handling in the padding decode step creates a Bleichenbacher-style oracle. An attacker who can submit ciphertexts and observe distinguishable outcomes can iteratively refine guesses about the plaintext or session key. This class of flaw is well documented in cryptographic literature and requires constant-time, indistinguishable failure paths to remediate.
Attack Vector
Exploitation requires a local attacker holding low privileges on a device running affected Qualcomm firmware. The attacker interacts with a component that performs RSA PKCS decryption or signature verification and submits crafted ciphertexts. By analyzing the response behavior, timing, or error signaling of the padding decode routine, the attacker infers information about the underlying plaintext. Repeated queries can recover keys, session material, or manipulate signed data, undermining confidentiality and integrity guarantees provided by the affected cryptographic module.
// No verified proof-of-concept code is publicly available for CVE-2025-21482.
// Refer to the Qualcomm Security Bulletin September 2025 for advisory details.
Detection Methods for CVE-2025-21482
Indicators of Compromise
- No public indicators of compromise have been published for CVE-2025-21482 at the time of writing.
- Unusual volumes of RSA decryption or signature verification requests originating from a single local process may warrant review.
Detection Strategies
- Inventory Qualcomm-based devices using CPE data and vendor firmware identifiers to establish exposure to the September 2025 bulletin.
- Monitor privileged local processes that interact with cryptographic services or trusted execution components for anomalous query patterns.
- Correlate firmware versions against the fixed builds listed in the Qualcomm Security Bulletin September 2025.
Monitoring Recommendations
- Track OEM firmware update rollouts to confirm patched builds reach production devices, especially in mobile, automotive, and IoT fleets.
- Log and alert on repeated cryptographic operation failures from local applications, which may indicate padding oracle probing.
- Review Mobile Device Management (MDM) telemetry for devices lagging on vendor security patch levels dated September 2025 or later.
How to Mitigate CVE-2025-21482
Immediate Actions Required
- Apply firmware updates provided by device OEMs that incorporate Qualcomm's September 2025 security bulletin fixes.
- Prioritize patching for devices exposed to untrusted local applications, including mobile handsets, automotive head units, and shared IoT gateways.
- Restrict installation of untrusted applications on affected devices until firmware updates are deployed.
Patch Information
Qualcomm published fixes for CVE-2025-21482 in the Qualcomm Security Bulletin September 2025. Because the flaw affects firmware distributed by device manufacturers, remediation depends on OEMs integrating Qualcomm's patched components and shipping updated builds to end users. Verify each product's security patch level against the vendor advisory.
Workarounds
- No vendor-supplied workaround is available; firmware update is the required remediation path.
- Reduce local attack surface by removing unnecessary applications and enforcing least-privilege access on affected devices.
- Isolate cryptographically sensitive workloads on devices that cannot be immediately patched.
# Example: verify Android security patch level on an affected device
adb shell getprop ro.build.version.security_patch
# Confirm the value reflects September 2025 or later, per OEM guidance
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
