High

CVE-2026-20125 — A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE…

A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE Software Release 3E could allow an authenticated, remote attacker to cause an affected device to reload unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper validation of user-supplied input. An attacker could exploit this vulnerability by sending malformed HTTP requests to an affected device. A successful exploit could allow the attacker to cause a watchdog timer to expire and the device to reload, resulting in a DoS condition. To exploit this vulnerability, the attacker must have a valid user account.

Published Mar 25, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: cisco

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.3% (30-day exploitation probability)+3
Technical severity (high)+6

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.28%

ahead of 19% of scored CVEs · Oct 14, 2026

Affects

Cisco

Cisco IOS XE Software and 1 more

CVSS base

7.7

High · 2 source(s)

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Partial

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Cisco Cisco IOS XE Software, Cisco Ios).
No fix documented in the sources: reduce exposure and monitor the vendor advisory.
Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Cisco	Cisco IOS XE Software	version 3.11.1aEversion 3.11.13Eversion 3.11.12Eversion 3.11.11Eversion 3.11.10Eversion 3.11.9Eversion 3.11.8Eversion 3.11.7E and 149 more version 3.11.6Eversion 3.11.5Eversion 3.11.3aEversion 3.11.4Eversion 3.9.1Eversion 3.11.3Eversion 3.11.2Eversion 3.11.1Eversion 3.11.0Eversion 3.10.3Eversion 3.10.2Eversion 3.10.0cEversion 3.10.1Eversion 3.10.0Eversion 3.9.2Eversion 3.13.0Sversion 3.13.1Sversion 3.13.2Sversion 3.13.3Sversion 3.13.4Sversion 3.13.5Sversion 3.13.2aSversion 3.13.0aSversion 3.13.5aSversion 3.13.6Sversion 3.13.7Sversion 3.13.6aSversion 3.13.7aSversion 3.13.8Sversion 3.13.9Sversion 3.13.10Sversion 3.6.0Eversion 3.6.1Eversion 3.6.2aEversion 3.6.2Eversion 3.6.3Eversion 3.6.4Eversion 3.6.5Eversion 3.6.6Eversion 3.6.5aEversion 3.6.7Eversion 3.6.8Eversion 3.6.7bEversion 3.6.9Eversion 3.6.10Eversion 3.14.0Sversion 3.14.1Sversion 3.14.2Sversion 3.14.3Sversion 3.14.4Sversion 3.15.0Sversion 3.15.1Sversion 3.15.2Sversion 3.15.1cSversion 3.15.3Sversion 3.15.4Sversion 3.7.0Eversion 3.7.1Eversion 3.7.2Eversion 3.7.3Eversion 3.7.4Eversion 3.7.5Eversion 3.5.0SQversion 3.5.1SQversion 3.5.2SQversion 3.5.3SQversion 3.5.4SQversion 3.5.5SQversion 3.5.6SQversion 3.5.7SQversion 3.5.8SQversion 3.16.0Sversion 3.16.1Sversion 3.16.1aSversion 3.16.2Sversion 3.16.2aSversion 3.16.0cSversion 3.16.3Sversion 3.16.2bSversion 3.16.3aSversion 3.16.4Sversion 3.16.4aSversion 3.16.4bSversion 3.16.5Sversion 3.16.4dSversion 3.16.6Sversion 3.16.7Sversion 3.16.6bSversion 3.16.7aSversion 3.16.7bSversion 3.16.8Sversion 3.16.9Sversion 3.16.10Sversion 3.17.0Sversion 3.17.1Sversion 3.17.2Sversion 3.17.1aSversion 3.17.3Sversion 3.17.4Sversion 3.8.0Eversion 3.8.1Eversion 3.8.2Eversion 3.8.3Eversion 3.8.4Eversion 3.8.5Eversion 3.8.5aEversion 3.8.6Eversion 3.8.7Eversion 3.8.8Eversion 3.8.9Eversion 3.8.10Eversion 3.18.0aSversion 3.18.0Sversion 3.18.1Sversion 3.18.2Sversion 3.18.3Sversion 3.18.4Sversion 3.18.0SPversion 3.18.1SPversion 3.18.1aSPversion 3.18.1bSPversion 3.18.1cSPversion 3.18.2SPversion 3.18.2aSPversion 3.18.3SPversion 3.18.4SPversion 3.18.3aSPversion 3.18.3bSPversion 3.18.5SPversion 3.18.6SPversion 3.18.7SPversion 3.18.8aSPversion 3.18.9SPversion 3.9.0Eversion 3.5.0Eversion 3.5.1Eversion 3.5.2Eversion 3.5.3Eversion 3.11.1Sversion 3.11.2Sversion 3.11.0Sversion 3.11.3Sversion 3.11.4Sversion 3.12.0Sversion 3.12.1Sversion 3.12.2Sversion 3.12.3Sversion 3.12.0aSversion 3.12.4S	Vulnerable	CVE Program (cve.org) e CISA ADP
Cisco	Ios	version 15.8(3)M4version 15.8(3)M3aversion 15.8(3)M3bversion 15.8(3)M5version 15.8(3)M6version 15.8(3)M7version 15.8(3)M8version 15.8(3)M9 and 135 more version 15.9(3)Mversion 15.9(3)M1version 15.9(3)M0aversion 15.9(3)M2version 15.9(3)M3version 15.9(3)M2aversion 15.9(3)M3aversion 15.9(3)M4version 15.9(3)M3bversion 15.9(3)M5version 15.9(3)M4aversion 15.9(3)M6version 15.9(3)M7version 15.9(3)M6aversion 15.9(3)M6bversion 15.9(3)M8version 15.9(3)M7aversion 15.9(3)M9version 15.9(3)M8bversion 15.9(3)M10version 15.9(3)M11version 15.9(3)M12version 15.3(3)JKversion 15.3(3)JK1version 15.3(3)JK2version 15.3(3)JK3version 15.3(3)JK2aversion 15.3(3)JK1tversion 15.3(3)JK4version 15.3(3)JK5version 15.3(3)JK6version 15.3(3)JK7version 15.3(3)JK8version 15.3(3)JK8aversion 15.3(3)JK8bversion 15.3(3)JK9version 15.3(3)JK10version 15.3(3)JK11version 15.3(3)JJversion 15.3(3)JJ1version 15.3(3)JPI1version 15.3(3)JPI4version 15.3(3)JPI1tversion 15.3(3)JPI5version 15.3(3)JPI7version 15.3(3)JPI6aversion 15.3(3)JPI8aversion 15.3(3)JPI9version 15.3(3)JPI10version 15.3(3)JPJ2version 15.3(3)JPJ3version 15.3(3)JPJ2tversion 15.3(3)JPJ3aversion 15.3(3)JPJ4version 15.3(3)JPJ5version 15.3(3)JPJ6version 15.3(3)JPJ7version 15.3(3)JPJ7cversion 15.3(3)JPJ8aversion 15.3(3)JPJ9version 15.3(3)JPJ10version 15.3(3)JPJ11version 15.3(3)JPKversion 15.3(3)JPK1version 15.3(3)JPK2version 15.3(3)JPK3version 15.3(3)JPK4version 15.3(3)JPK5version 15.3(3)JPK6version 15.3(3)JPK7version 15.3(3)JPK8version 15.3(3)JPK9version 15.3(3)JPLversion 15.3(3)JPMversion 15.3(3)JPNversion 15.3(3)JPN1version 15.3(3)JPN2version 15.3(3)JPN3version 15.3(3)JPN4version 15.3(3)JPN5version 15.3(3)JPN6version 15.3(3)JPN7version 15.3(3)JPOversion 15.3(3)JPPversion 15.3(3)JPQversion 15.3(3)JPQ1version 15.3(3)JPQ2version 15.3(3)JPQ3version 15.3(3)JPQ4version 15.3(3)JPQ5version 15.3(3)JPRversion 15.3(3)JPSversion 15.3(3)JPTversion 15.3(3)JPT1version 15.3(3)JPT2version 15.3(3)JPT3version 12.2(33)CYversion 12.2(33)CY1version 12.2(33)CY2version 12.2(55)SEversion 12.2(55)SE3version 12.2(55)SE2version 12.2(58)SEversion 12.2(55)SE1version 12.2(58)SE1version 12.2(55)SE4version 12.2(58)SE2version 12.2(55)SE5version 12.2(55)SE6version 12.2(55)SE7version 12.2(55)SE8version 12.2(55)SE9version 12.2(55)SE10version 12.2(55)SE11version 12.2(55)SE12version 12.2(55)SE13version 12.2(25)EZversion 12.2(25)EZ1version 12.2(58)EZversion 12.2(53)EZversion 12.2(55)EZversion 12.2(60)EZversion 12.2(60)EZ1version 12.2(60)EZ2version 12.2(60)EZ3version 12.2(60)EZ4version 12.2(60)EZ5version 12.2(60)EZ6version 12.2(60)EZ7version 12.2(60)EZ8version 12.2(60)EZ9version 12.2(60)EZ10version 12.2(60)EZ11version 12.2(60)EZ12version 12.2(60)EZ13	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

Low

User interaction

None

Scope

Changed

Confidentiality

None

Integrity

None

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.7	CVSS 3.1	High	3.1	4.0	psirt@cisco.com via NIST National Vulnerability Database
7.7	CVSS 3.1	High	—	—	cisco via CVE Program (cve.org) e CISA ADP

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:N/A:H (score shown at the top: psirt@cisco.com)

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-228

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.28%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).

web/proxy/WAF logsnetwork IDS/IPS

Timeline

What happened to this CVE, newest first.

2026
Affected products added · cisco/ios, cisco/cisco ios xe software
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
CVSS changed · 7.7
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Awaiting Analysis
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Mar 25, 2026 · cisco

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

1 on the record

sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ios-http-dos-s
NIST National Vulnerability Database

Elsewhere on this site

Cisco
every CVE for this vendor

CWE-228
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-20115 Cleartext Transmission of Sensitive Information in Cisco Cisco IOS XE Software Mar 25, 2026
Medium CVE-2026-20114 A vulnerability in the Lobby Ambassador web-based management API of Cisco IOS XE… Mar 25, 2026
Medium CVE-2026-20113 A vulnerability in the web-based Cisco IOx application hosting environment management… Mar 25, 2026
Medium CVE-2026-20112 Cross-site Scripting (XSS) in Cisco Cisco IOS XE Software Mar 25, 2026
Medium CVE-2026-20104 A vulnerability in the bootloader of Cisco IOS XE Software for Cisco Catalyst 9200… Mar 25, 2026
Medium CVE-2026-20110 A vulnerability in the CLI of Cisco IOS XE Software could allow an authenticated, local… Mar 25, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No fixed version, patch or mitigation documented.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-20125 is "A vulnerability in the HTTP Server feature of Cisco IOS Software and Cisco IOS XE…", rated High. It affects Cisco IOS XE Software (Cisco); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 7.7 describes technical severity. EPSS 0.28% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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