{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-1356 in the wild and no public exploit code.","fix":"No fix has been published for CVE-2021-1356 yet. Limit exposure of the affected software until one is available.","what":"CVE-2021-1356 is a medium-severity denial of service vulnerability in Cisco Ios Xe, published on 24 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-1356 and fix it if it is affected.\n\nWhat it is: CVE-2021-1356 is a medium-severity denial of service vulnerability in Cisco Ios Xe, published on 24 Mar 2021. Any signed-in user can exploit it over the network, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-1356 in the wild and no public exploit code.\n\nAffected product: Cisco Ios Xe. No package-level version data is available, so check the vendor advisory linked from the reference page.\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2021-1356/ (Markdown: https://insights.sbomify.com/CVE-2021-1356/index.md)","id":"CVE-2021-1356","markdown":"https://insights.sbomify.com/CVE-2021-1356/index.md","name":"CVE-2021-1356","record":{"aliases":["GHSA-7rw7-xm59-wmr8"],"analysis":{"component_type":"network_device","fix_type":"patch","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"Cisco IOS XE","requires_auth":"low_privilege","summary":"Authenticated attackers can cause denial of service in Cisco IOS XE web UI by sending crafted HTTP packets, requiring manual intervention to restore.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"cisco","cpe":[{"product":"ios_xe","vendor":"cisco"}],"cvss":{"score":4.3,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L","version":"3.1"},"cwes":[{"id":"CWE-755","name":"Improper Handling of Exceptional Conditions"},{"id":"CWE-20","name":"Improper Input Validation"}],"description":"Multiple vulnerabilities in the web UI of Cisco IOS XE Software could allow an authenticated, remote attacker with read-only privileges to cause the web UI software to become unresponsive and consume vty line instances, resulting in a denial of service (DoS) condition. These vulnerabilities are due to insufficient error handling in the web UI. An attacker could exploit these vulnerabilities by sending crafted HTTP packets to an affected device. A successful exploit could allow the attacker to cause the web UI software to become unresponsive and consume all available vty lines, preventing new session establishment and resulting in a DoS condition. Manual intervention would be required to regain web UI and vty session functionality. Note: These vulnerabilities do not affect the console connection.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"Cisco IOS XE Software Web UI Denial of Service Vulnerabilities","id":"CVE-2021-1356","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"cisco:ios_xe","products":["cisco:ios_xe"],"type":"denial_of_service","year":"2021"},"n_packages":0,"n_references":1,"next":{"headline":"Cisco Unified Communications Products Vulnerabilities","id":"CVE-2021-1357"},"packages":[],"prev":{"headline":"Cisco Unified Communications Products Vulnerabilities","id":"CVE-2021-1355"},"products":["Cisco IOS XE Software"],"published":"2021-03-24","related":[{"cvss_score":10,"headline":"Cisco IOS XE Web UI Privilege Escalation","id":"CVE-2023-20198","kev_date_added":"2023-10-16","published":"2023-10-16"},{"cvss_score":9.8,"headline":"Cisco IOS Software and Cisco IOS XE Software Quality of Service Remote Code Execution","id":"CVE-2018-0151","kev_date_added":"2022-03-03","published":"2018-03-28"},{"cvss_score":7.2,"headline":"Cisco IOS XE Web UI Command Injection","id":"CVE-2023-20273","kev_date_added":"2023-10-23","published":"2023-10-24"},{"cvss_score":10,"headline":"Hardcoded credentials in Cisco IOS XE Software","id":"CVE-2025-20188","kev_date_added":null,"published":"2025-05-07"},{"cvss_score":10,"headline":"Cisco IOS XE Software for Catalyst 9000 Family Wireless Controllers CAPWAP Remote Code Execution Vulnerability","id":"CVE-2021-34770","kev_date_added":null,"published":"2021-09-23"},{"cvss_score":10,"headline":"Cisco REST API Container for IOS XE Software Authentication Bypass Vulnerability","id":"CVE-2019-12643","kev_date_added":null,"published":"2019-08-28"},{"cvss_score":9.8,"headline":"Cisco IOS XE Software Security Hardening Release","id":"CVE-2026-20272","kev_date_added":null,"published":"2026-08-05"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2024-11-08","vendors":["Cisco"]},"summary":"Authenticated attackers can cause denial of service in Cisco IOS XE web UI by sending crafted HTTP packets, requiring manual intervention to restore.","url":"https://insights.sbomify.com/CVE-2021-1356/"}