Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:XSummary
CVE-2025-9938 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Dlink Di-8400 Firmware. Its CVSS base score is 7.4 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 28% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
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-2025-9938 is a stack-based buffer overflow vulnerability affecting the D-Link DI-8400 router running firmware version 16.07.26A1. The issue resides in the yyxz_dlink_asp function within the /yyxz.asp file, where manipulation of the ID argument triggers the overflow. This flaw, associated with CWEs-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer), CWE-121 (Stack-based Buffer Overflow), and CWE-787 (Out-of-bounds Write), has a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity.
The vulnerability can be exploited remotely by an attacker with low privileges (PR:L), requiring network access and low complexity with no user interaction needed. Successful exploitation allows high-impact consequences, including unauthorized disclosure of confidential information, modification of data or system integrity, and denial of service through availability disruption, potentially leading to remote code execution on the affected device.
Advisories and references, including entries on VulDB (ctiid.322340, id.322340, submit.643446), highlight the issue but do not specify patches or vendor mitigations in the available details. Proof-of-concept exploits are publicly available on GitHub repositories targeting the /yyxz.asp endpoint, increasing the risk of widespread exploitation.
Notable context includes the public availability of exploits, published on 2025-09-04, which elevates the urgency for affected users to monitor and isolate vulnerable devices pending further vendor guidance.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-26658
Vulnerability Data
A weakness has been identified in D-Link DI-8400 16.07.26A1. The affected element is the function yyxz_dlink_asp of the file /yyxz.asp. This manipulation of the argument ID causes stack-based buffer overflow. It is possible to initiate the attack remotely. The exploit…
more
has been made available to the public and could be exploited.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 2 hardening rules · 2 OS baselines
V17.3.2
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and analysis can discover stack-buffer overflows before deployment.
Input validation directly stops untrusted data from exceeding stack buffer bounds.
Memory-protection mechanisms limit the ability to execute injected code after a stack overflow.
Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.
Secure engineering principles require memory-safe design and coding that structurally avoids buffer-boundary violations.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices (bounds checking, safe APIs, reviews) directly prevent this class of flaw.
Vulnerability scanning and code analysis directly surface buffer-boundary flaws.
Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.
Developer training on secure coding reduces introduction of memory-buffer errors.
Patching replaces vulnerable code containing buffer-boundary defects.
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.
Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.
Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.
Application security requirements can specify memory-safety rules, but do not prescribe implementation details.
Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.
Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.
Change management can enforce review gates that catch unsafe memory operations before deployment.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (1 rule)
- V-248594 OL 8 must implement address space layout randomization (ASLR) to protect its memory from unauthorized code execution. prevents CWE-121
Oracle Linux 9 (1 rule)
- V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-121