Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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-2026-23957 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Lxsmnsyc Seroval. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 37th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-10 (Concurrent Session Control) and SC-6 (Resource Availability) — 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-2026-23957 is a denial-of-service vulnerability in the seroval JavaScript library, which enables serialization of JavaScript values including complex structures beyond standard JSON.stringify capabilities. In versions 1.4.0 and below, attackers can override encoded array lengths in serialized data by replacing them with excessively large values, causing the deserialization process to consume significant processing time due to resource exhaustion (CWE-770). The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Any remote, unauthenticated attacker can exploit this vulnerability by crafting and delivering malicious serialized payloads to applications that use affected seroval versions for deserialization. Successful exploitation leads to substantial increases in CPU usage during deserialization, potentially resulting in denial of service for the targeted application or service without requiring user interaction.
The issue has been addressed in seroval version 1.4.1. Official mitigation guidance is available in the GitHub security advisory at https://github.com/lxsmnsyc/seroval/security/advisories/GHSA-66fc-rw6m-c2q6 and the fixing commit at https://github.com/lxsmnsyc/seroval/commit/ce9408ebc87312fcad345a73c172212f2a798060; security practitioners should upgrade to the patched version and validate input serialization/deserialization processes.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-3668
Vulnerability Data
seroval facilitates JS value stringification, including complex structures beyond JSON.stringify capabilities. In versions 1.4.0 and below, overriding encoded array lengths by replacing them with an excessively large value causes the deserialization process to significantly increase processing time. This issue has…
more
been fixed in version 1.4.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 5 hardening rules · 3 OS baselines
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Mitigating Controls (NIST 800-53 r5) AI
Directly enforces a hard limit on concurrent sessions, structurally preventing unbounded resource allocation.
Requires explicit allocation of resources by priority or quota, directly stopping unlimited allocation.
Imposes a limit on consecutive invalid attempts, preventing one specific class of unbounded resource consumption.
Reduces impact of resulting DoS events without preventing the underlying lack of allocation limits.
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.
Monitoring capacity and taking action to maintain availability directly reduces unchecked resource allocation.
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.
Baseline comparison of CPU, memory and bandwidth usage helps surface uncontrolled resource allocations before they cause service degradation.
A.8.6's monitoring, stress-testing, projections, resource utilization tracking, and explicit demand-reduction steps (e.g. optimizing queries, denying non-critical bandwidth, decommissioning) directly stop uncontrolled allocation from being exploited in most cases; the bounded remainder is resources whose limits live only in code that the capacity plan does not rewrite.
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` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. blocks CWE-770
- V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. blocks CWE-770
Oracle Linux 9 (2 rules)
- V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. blocks CWE-770
- V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. blocks CWE-770
RHEL 8 (1 rule)
- V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. blocks CWE-770