CVE-2020-29557
Memory Safety in Dlink Dir-825 R1 Firmware ≤ 3.0.1
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2020-29557 is a critical-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Dlink Dir-825\/Ac. Its CVSS base score is 9.8 (Critical).
Operationally, ranked in the top 1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2020-29557 is a buffer overflow vulnerability (CWE-119) affecting the web interface on D-Link DIR-825 R1 devices running firmware versions through 3.0.1. The flaw was addressed in updates released on or after 2020-11-20. It carries a CVSS 3.1 base score of 9.8, reflecting network attackability, low complexity, and no required authentication or user interaction.
An unauthenticated attacker with network access to the device can send a crafted request to the web interface, triggering the overflow to execute arbitrary code. Successful exploitation grants full control of the affected router, enabling actions such as credential theft, traffic interception, or use as a pivot point into connected networks.
D-Link has published updated firmware for the DIR-825 R1 via its Russian support site. The vulnerability appears in CISA's catalog of known exploited vulnerabilities, confirming observed in-the-wild attacks.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2020-21920
Vulnerability Data
An issue was discovered on D-Link DIR-825 R1 devices through 3.0.1 before 2020-11-20. A buffer overflow in the web interface allows attackers to achieve pre-authentication remote code execution.
- CWE(s)
- KEV Date Added
- 03 November 2021
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Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.
Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.
Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.
Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
A.8.25 mandates secure SDLC practices (secure coding guidelines, security requirements, testing including code scans and penetration tests, developer training) that reach buffer management and can stop many buffer overruns from reaching production, but leaves a bounded remainder (e.g. flaws in non-software components, incomplete enforcement of guidelines, or post-deployment changes)
Application security requirements can specify memory-safety rules, but do not prescribe implementation details.
A.8.27 mandates security-by-design principles (e.g. least privilege, fail securely, distrust external input, hardening) plus design reviews that can catch and stop buffer-boundary errors before they reach code, but this is only one minority slice of CWE-119's broad surface (language-specific flaws, unsafe library use, compiler/runtime mitigations, and post-deployment instances remain outside its direct scope).
Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.
Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.
Hardening callouts derived
DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.
- No fine-grained STIG row for CWE-119, a class-level weakness. Rules are authored against its narrower children: CWE-823.