CVE-2021-34699
Cisco IOS and IOS XE Software TrustSec CLI Parser Denial of Service Vulnerability
HIGH
7.7
CVSS Score
Published: September 23, 2021 at 02:25 AM UTC
Updated: June 17, 2026 at 03:56 AM UTC
2 products affected across 1 vendorIOSIOS Xe
Using Cisco IOS by Cisco?
Get instant alerts when new vulnerabilities affect Cisco IOS - before attackers find them.
Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.7
Exploit prediction
EPSS 1%
SSVC
No known exploit
Description
A vulnerability in the TrustSec CLI parser of Cisco IOS and Cisco IOS XE Software could allow an authenticated, remote attacker to cause an affected device to reload. This vulnerability is due to an improper interaction between the web UI and the CLI parser. An attacker could exploit this vulnerability by requesting a particular CLI command to be run through the web UI. A successful exploit could allow the attacker to cause the device to reload, resulting in a denial of service (DoS) condition.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
12.2(6)i115.0(1)sy15.0(1)sy115.0(1)sy1015.0(1)sy215.0(1)sy315.0(1)sy415.0(1)sy515.0(1)sy615.0(1)sy715.0(1)sy7a15.0(1)sy815.0(1)sy915.0(2)ej15.0(2)ej115.0(2)ek15.0(2)ek115.0(2)ex15.0(2)ex115.0(2)ex1015.0(2)ex1115.0(2)ex1215.0(2)ex1315.0(2)ex215.0(2)ex315.0(2)ex415.0(2)ex515.0(2)ex615.0(2)ex715.0(2)ex815.0(2)ey15.0(2)ey115.0(2)ey215.0(2)ey315.0(2)ez15.0(2)se15.0(2)se115.0(2)se1015.0(2)se10a15.0(2)se1115.0(2)se1215.0(2)se1315.0(2)se13a15.0(2)se13b15.0(2)se215.0(2)se315.0(2)se415.0(2)se515.0(2)se615.0(2)se715.0(2)se815.0(2)se915.0(2a)ex515.0(2a)se915.1(1)sy15.1(1)sy115.1(1)sy215.1(1)sy315.1(1)sy415.1(1)sy515.1(1)sy615.1(2)sy15.1(2)sy115.1(2)sy1015.1(2)sy1115.1(2)sy1215.1(2)sy1315.1(2)sy1415.1(2)sy1515.1(2)sy1615.1(2)sy16a15.1(2)sy215.1(2)sy315.1(2)sy415.1(2)sy4a15.1(2)sy515.1(2)sy615.1(2)sy715.1(2)sy815.1(2)sy915.1(3)svr115.1(3)svr215.1(3)svr315.1(3)svs15.1(3)svs115.1(3)svt115.1(3)svt215.2(1)e15.2(1)e115.2(1)e215.2(1)e315.2(1)ey15.2(1)sy15.2(1)sy0a15.2(1)sy115.2(1)sy1a15.2(1)sy215.2(1)sy315.2(1)sy415.2(1)sy515.2(1)sy615.2(1)sy715.2(1)sy815.2(2)e15.2(2)e115.2(2)e1015.2(2)e10a15.2(2)e10b15.2(2)e215.2(2)e315.2(2)e415.2(2)e515.2(2)e5a15.2(2)e5b15.2(2)e615.2(2)e715.2(2)e7b15.2(2)e815.2(2)e915.2(2)e9a15.2(2)ea15.2(2)ea115.2(2)ea215.2(2)ea315.2(2)eb15.2(2)eb115.2(2)eb215.2(2)sy15.2(2)sy115.2(2)sy215.2(2)sy315.2(2a)e115.2(2a)e215.2(2b)e15.2(3)e15.2(3)e115.2(3)e215.2(3)e315.2(3)e415.2(3)e515.2(3)ea15.2(3a)e15.2(3m)e215.2(3m)e715.2(3m)e815.2(4)e15.2(4)e115.2(4)e1015.2(4)e10a15.2(4)e10b15.2(4)e10c15.2(4)e215.2(4)e315.2(4)e415.2(4)e515.2(4)e5a15.2(4)e615.2(4)e715.2(4)e815.2(4)e915.2(4)ea15.2(4)ea115.2(4)ea215.2(4)ea315.2(4)ea415.2(4)ea515.2(4)ea615.2(4)ea715.2(4)ea815.2(4)ea915.2(4)ea9a15.2(4)ec115.2(4)ec215.2(4m)e115.2(4m)e215.2(4m)e315.2(4n)e215.2(4o)e215.2(4o)e315.2(4p)e115.2(4q)e115.2(4s)e115.2(5)e15.2(5)e115.2(5)e215.2(5)e2b15.2(5)e2c15.2(5)ea15.2(5)ex15.2(5a)e15.2(5a)e115.2(5b)e15.2(5c)e15.2(6)e15.2(6)e0a15.2(6)e0c15.2(6)e115.2(6)e1a15.2(6)e1s15.2(6)e215.2(6)e2a15.2(6)e2b15.2(6)e315.2(6)eb15.2(7)e15.2(7)e0a15.2(7)e0b15.2(7)e0s15.2(7)e115.2(7)e1a15.2(7)e215.2(7)e2a15.2(7)e2b15.2(7)e315.2(7)e3a15.2(7)e3k15.2(7)e415.2(7)e9915.2(7a)e0b15.2(7b)e0b15.2(8)e15.3(0)sy15.3(1)sy15.3(1)sy115.3(1)sy215.3(3)jd15.3(3)jd1115.3(3)jd1215.3(3)jd1315.3(3)jd1415.3(3)jd1615.3(3)jd1715.3(3)jd215.3(3)jd315.3(3)jd415.3(3)jd515.3(3)jd615.3(3)jd715.3(3)jd815.3(3)jd915.3(3)je15.3(3)jf15.3(3)jf115.3(3)jf1015.3(3)jf1115.3(3)jf1215.3(3)jf12i15.3(3)jf1415.3(3)jf14i15.3(3)jf215.3(3)jf415.3(3)jf515.3(3)jf615.3(3)jf715.3(3)jf815.3(3)jf915.3(3)jg15.3(3)jg115.3(3)jh15.3(3)jh115.3(3)ji115.3(3)ji315.3(3)ji415.3(3)ji515.3(3)ji615.3(3)jj15.3(3)jj115.3(3)jk15.3(3)jk115.3(3)jk1t15.3(3)jk215.3(3)jk2a15.3(3)jk315.3(3)jk415.3(3)jk515.3(3)jpi115.3(3)jpi1t15.3(3)jpi415.3(3)jpi515.3(3)jpi5s15.3(3)jpi6a15.3(3)jpi715.3(3)jpj215.3(3)jpj2t15.3(3)jpj315.3(3)jpj3a15.3(3)jpj415.3(3)jpj515.3(3)jpj615.3(3)jpk15.3(3)jpk115.4(1)cg15.4(1)cg115.4(1)s15.4(1)s115.4(1)s215.4(1)s315.4(1)s415.4(1)sy15.4(1)sy115.4(1)sy215.4(1)sy315.4(1)sy415.4(1)t15.4(1)t115.4(1)t215.4(1)t315.4(1)t415.4(2)cg15.4(2)s15.4(2)s115.4(2)s215.4(2)s315.4(2)s415.4(2)sn15.4(2)sn115.4(2)t15.4(2)t115.4(2)t215.4(2)t315.4(2)t415.4(3)m15.4(3)m115.4(3)m1015.4(3)m215.4(3)m315.4(3)m415.4(3)m515.4(3)m615.4(3)m6a15.4(3)m715.4(3)m7a15.4(3)m815.4(3)m915.4(3)s15.4(3)s0d15.4(3)s0e15.4(3)s0f15.4(3)s115.4(3)s1015.4(3)s215.4(3)s315.4(3)s415.4(3)s515.4(3)s615.4(3)s6a15.4(3)s715.4(3)s815.4(3)s915.4(3)sn115.4(3)sn1a15.5(1)s15.5(1)s115.5(1)s215.5(1)s315.5(1)s415.5(1)sn15.5(1)sn115.5(1)sy15.5(1)sy115.5(1)sy215.5(1)sy315.5(1)sy415.5(1)sy515.5(1)sy615.5(1)sy715.5(1)t15.5(1)t115.5(1)t215.5(1)t315.5(1)t415.5(2)s15.5(2)s115.5(2)s215.5(2)s315.5(2)s415.5(2)sn15.5(2)t15.5(2)t115.5(2)t215.5(2)t315.5(2)t415.5(2)xb15.5(3)m15.5(3)m0a15.5(3)m115.5(3)m1015.5(3)m1115.5(3)m215.5(3)m2a15.5(3)m315.5(3)m415.5(3)m4a15.5(3)m4b15.5(3)m4c15.5(3)m515.5(3)m615.5(3)m6a15.5(3)m715.5(3)m815.5(3)m915.5(3)s15.5(3)s0a15.5(3)s115.5(3)s1015.5(3)s10a15.5(3)s10b15.5(3)s10c15.5(3)s1a15.5(3)s215.5(3)s315.5(3)s415.5(3)s515.5(3)s615.5(3)s6a15.5(3)s6b15.5(3)s715.5(3)s815.5(3)s915.5(3)s9a15.5(3)sn15.5(3)sn0a15.6(1)s15.6(1)s115.6(1)s215.6(1)s315.6(1)s415.6(1)sn15.6(1)sn115.6(1)sn215.6(1)sn315.6(1)t15.6(1)t0a15.6(1)t115.6(1)t215.6(1)t315.6(2)s15.6(2)s115.6(2)s215.6(2)s315.6(2)s415.6(2)sn15.6(2)sp15.6(2)sp115.6(2)sp1015.6(2)sp215.6(2)sp315.6(2)sp415.6(2)sp515.6(2)sp615.6(2)sp715.6(2)sp815.6(2)sp8a15.6(2)sp915.6(2)t15.6(2)t0a15.6(2)t115.6(2)t215.6(2)t315.6(3)m15.6(3)m0a15.6(3)m115.6(3)m1a15.6(3)m1b15.6(3)m215.6(3)m2a15.6(3)m315.6(3)m3a15.6(3)m415.6(3)m515.6(3)m615.6(3)m6a15.6(3)m6b15.6(3)m715.6(3)m815.6(3)m915.6(3)sn15.6(4)sn15.6(5)sn15.6(7)sn15.6(7)sn115.6(7)sn215.7(3)m15.7(3)m0a15.7(3)m115.7(3)m215.7(3)m315.7(3)m415.7(3)m4a15.7(3)m4b15.7(3)m515.7(3)m615.7(3)m715.7(3)m815.8(3)m15.8(3)m0a15.8(3)m0b15.8(3)m115.8(3)m1a15.8(3)m215.8(3)m2a15.8(3)m315.8(3)m3a15.8(3)m3b15.8(3)m415.8(3)m515.8(3)m615.9(3)m15.9(3)m0a15.9(3)m115.9(3)m215.9(3)m2a15.9(3)m315.9(3)m3a15.9(3)m3b
16.1.116.1.216.1.316.10.116.10.1a16.10.1b16.10.1c16.10.1d16.10.1e16.10.1f16.10.1g16.10.1s16.10.216.10.316.11.116.11.1a16.11.1b16.11.1c16.11.1s16.11.216.12.116.12.1a16.12.1c16.12.1s16.12.1t16.12.1w16.12.1x16.12.1y16.12.1z16.12.1z116.12.1za16.12.216.12.2a16.12.2s16.12.2t16.12.316.12.3a16.12.3s16.12.416.12.4a16.12.516.12.5a16.12.5b16.2.116.2.216.3.116.3.1016.3.1116.3.1a16.3.216.3.316.3.416.3.516.3.5b16.3.616.3.716.3.816.3.916.4.116.4.216.4.316.5.116.5.1a16.5.1b16.5.216.5.316.6.116.6.216.6.316.6.416.6.4a16.6.4s16.6.516.6.5a16.6.5b16.6.616.6.716.6.7a16.6.816.6.916.7.116.7.1a16.7.1b16.7.216.7.316.7.416.8.116.8.1a16.8.1b16.8.1c16.8.1d16.8.1e16.8.1s16.8.216.8.316.9.116.9.1a16.9.1b16.9.1c16.9.1d16.9.1s16.9.216.9.2a16.9.2s16.9.316.9.3a16.9.3h16.9.3s16.9.416.9.4c16.9.516.9.5f16.9.616.9.717.1.117.1.1a17.1.1s17.1.1t17.1.217.1.317.2.117.2.1a17.2.1r17.2.1v17.2.217.2.317.3.117.3.1a17.3.1w17.3.1x17.3.1z17.3.217.3.2a17.3.317.3.3a17.4.117.4.1a17.4.1b17.4.1c17.5.117.5.1a3.10.0ce3.10.0e3.10.1ae3.10.1e3.10.1se3.10.2e3.10.3e3.11.0e3.11.0s3.11.1ae3.11.1e3.11.1s3.11.2ae3.11.2e3.11.2s3.11.3ae3.11.3e3.11.3s3.11.4e3.11.4s3.11.99ze3.12.0as3.12.0s3.12.1s3.12.2s3.12.3s3.12.4s3.13.0as3.13.0s3.13.10s3.13.1s3.13.2as3.13.2s3.13.3s3.13.4s3.13.5as3.13.5s3.13.6as3.13.6bs3.13.6s3.13.7as3.13.7s3.13.8s3.13.9s3.14.0s3.14.1s3.14.2s3.14.3s3.14.4s3.15.0s3.15.1cs3.15.1s3.15.1xbs3.15.2s3.15.2xbs3.15.3s3.15.4s3.16.0as3.16.0bs3.16.0cs3.16.0s3.16.10as3.16.10bs3.16.10cs3.16.10s3.16.1as3.16.1s3.16.2as3.16.2bs3.16.2s3.16.3as3.16.3s3.16.4as3.16.4bs3.16.4cs3.16.4ds3.16.4es3.16.4gs3.16.4s3.16.5as3.16.5bs3.16.5s3.16.6bs3.16.6s3.16.7as3.16.7bs3.16.7s3.16.8s3.16.9s3.17.0s3.17.1as3.17.1s3.17.2s3.17.3s3.17.4s3.18.0as3.18.0s3.18.0sp3.18.10sp3.18.1asp3.18.1bsp3.18.1csp3.18.1gsp3.18.1hsp3.18.1isp3.18.1s3.18.1sp3.18.2asp3.18.2s3.18.2sp3.18.3asp3.18.3bsp3.18.3s3.18.3sp3.18.4s3.18.4sp3.18.5sp3.18.6sp3.18.7sp3.18.8asp3.18.8sp3.18.9sp3.3.0se3.3.0xo3.3.1se3.3.1xo3.3.2se3.3.2xo3.3.3se3.3.4se3.3.5se3.5.0e3.5.1e3.5.2e3.5.3e3.6.0ae3.6.0be3.6.0e3.6.10ae3.6.10e3.6.1e3.6.2ae3.6.2e3.6.3e3.6.4e3.6.5ae3.6.5be3.6.5e3.6.6e3.6.7ae3.6.7be3.6.7e3.6.8e3.6.9ae3.6.9e3.7.0e3.7.1e3.7.2e3.7.3e3.7.4e3.7.5e3.8.0e3.8.10ce3.8.10e3.8.1e3.8.2e3.8.3e3.8.4e3.8.5ae3.8.5e3.8.6e3.8.7e3.8.8e3.8.9e3.9.0e3.9.1e3.9.2be3.9.2e
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
References (1)
Vendor Advisoryx_refsource_CISCO
Source: [email protected]
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-trustsec-dos-7fuXDR2SSVC — Action Prioritization
SSVCNo known exploitNot automatablePartial impact
SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.
CVSS
7.7HIGHcisco
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- LOW
- User Interaction
- NONE
- Scope
- CHANGED
- Confidentiality
- NONE
- Integrity
- NONE
- Availability
- HIGH
Vector?
Quick Info
StatusMODIFIED
CWE
CWE-435CWE-436
Get alerted
Stop reading CVE feeds looking for your own stack
Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.
Free plan, no card