CVE-2020-1631
A vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP) allows an unauthenticated attacker to perform local file inclusion (LFI) or path traversal. Using this vulnerability, an attacker may be able to inject commands into the httpd.log, read files with 'world' readable permission file or obtain J-Web session tokens. In the case of command injection, as the HTTP service runs as user 'nobody', the impact of this command injection is limited. (CVSS score 5.3, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) In the case of reading files with 'world' readable permission, in Junos OS 19.3R1 and above, the unauthenticated attacker would be able to read the configuration file. (CVSS score 5.9, vector CVSS:3.1/ AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N) If J-Web is enabled, the attacker could gain the same level of access of anyone actively logged into J-Web. If an administrator is logged in, the attacker could gain administrator access to J-Web. (CVSS score 8.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled. Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf To summarize: If HTTP/HTTPS services are disabled, there is no impact from this vulnerability. If HTTP/HTTPS services are enabled and J-Web is not in use, this vulnerability has a CVSS score of 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N). If J-Web is enabled, this vulnerability has a CVSS score of 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Juniper SIRT has received a single report of this vulnerability being exploited in the wild. Out of an abundance of caution, we are notifying customers so they can take appropriate actions. Indicators of Compromise: The /var/log/httpd.log may have indicators that commands have injected or files being accessed. The device administrator can look for these indicators by searching for the string patterns "=*;*&" or "*%3b*&" in /var/log/httpd.log, using the following command: user@device> show log httpd.log | match "=*;*&|=*%3b*&" If this command returns any output, it might be an indication of malicious attempts or simply scanning activities. Rotated logs should also be reviewed, using the following command: user@device> show log httpd.log.0.gz | match "=*;*&|=*%3b*&" user@device> show log httpd.log.1.gz | match "=*;*&|=*%3b*&" Note that a skilled attacker would likely remove these entries from the local log file, thus effectively eliminating any reliable signature that the device had been attacked. This issue affects Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S16; 12.3X48 versions prior to 12.3X48-D101, 12.3X48-D105; 14.1X53 versions prior to 14.1X53-D54; 15.1 versions prior to 15.1R7-S7; 15.1X49 versions prior to 15.1X49-D211, 15.1X49-D220; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R3-S2 ; 18.4 version 18.4R2 and later versions; 19.1 versions prior to 19.1R1-S5, 19.1R3-S1; 19.1 version 19.1R2 and later versions; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2; 20.1 versions prior to 20.1R1-S1, 20.1R2.
- CVSS
- 8.8Highscored by the publisher (CNA)
- Exploited in the wild
- Yes, in CISA KEV since 25 Mar 2022CISA deadline for US federal agencies: 15 Apr 2022
- EPSS
- 4.9%chance of exploitation in the next 30 daystop 8% of scored CVEsFIRST score of 11 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 4 May 2020analysed here 12 Nov 2026
Do first. Apply updates per vendor instructions. (CISA's required action for this KEV entry)
Summary
Triage
- Attack surface
- Server-side
- Exploitable
- At runtime
- Attack vector
- network
- Can a WAF block it?
- Yes. See why
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| Juniper Networks Junos OS | >= 12.3 and < 12.3R12-S16>= 12.3X48 and < 12.3X48-D101, 12.3X48-D105>= 14.1X53 and < 14.1X53-D54>= 15.1 and < 15.1R7-S7>= 15.1X49 and < 15.1X49-D211, 15.1X49-D220>= 16.1 and < 16.1R7-S8>= 17.2 and < 17.2R3-S4>= 17.3 and < 17.3R3-S8>= 17.4 and < 17.4R2-S11, 17.4R3-S2>= 18.1 and < 18.1R3-S10>= 18.2 and < 18.2R2-S7, 18.2R3-S4>= 18.3 and < 18.3R2-S4, 18.3R3-S2>= 18.4 and < 18.4R1-S7, 18.4R3-S2>= 19.1 and < 19.1R1-S5, 19.1R3-S1>= 19.2 and < 19.2R2>= 19.3 and < 19.3R2-S3, 19.3R3>= 19.4 and < 19.4R1-S2, 19.4R2>= 20.1 and < 20.1R1-S1, 20.1R2Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- juniper:junos
Fix and mitigation
WAF and other mitigations
Can a WAF block it? Yes. Path traversal sends `../` sequences in the request, which WAF rules catch, including the common encodings. Azure WAF also publishes a rule written for this CVE.
Azure WAF · 1 rule
- 99001007 · Critical - 5
Also consider: canonical path validation
Based on WAF vendor rules published for this CVE. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Listed since 25 Mar 2022.
- CISA due date
- 15 Apr 2022, the remediation deadline for US federal agencies
- CISA required action
- Apply updates per vendor instructions.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation active, automatable no, technical impact totalAssessed by CISA 7 Feb 2025 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 4 May 2020Published
- 25 Mar 2022Added to CISA KEV (exploited in the wild)690 days (about 2 years) later
- 15 Apr 2022CISA remediation due date (US federal agencies)21 days later
- 7 Feb 2025CISA SSVC assessment: exploitation active1,030 days (about 3 years) later
- 21 Oct 2025CVE record last updated256 days (about 9 months) later
- 12 Nov 2026Analysed by vulneraibility.com387 days (about 1 year) later
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
| Metric | Value | What it means |
|---|---|---|
| Attack vector | NetworkReachable over the internet or any routable network. | Reachable over the internet or any routable network. |
| Attack complexity | LowRepeatable attack, no special conditions. | Repeatable attack, no special conditions. |
| Privileges required | NoneThe attacker needs no prior access. | The attacker needs no prior access. |
| User interaction | RequiredA victim must click, open or otherwise cooperate. | A victim must click, open or otherwise cooperate. |
| Scope | UnchangedImpact stays within the vulnerable component. | Impact stays within the vulnerable component. |
| Confidentiality | HighTotal data disclosure possible. | Total data disclosure possible. |
| Integrity | HighComplete modification possible. | Complete modification possible. |
| Availability | HighFull outage possible. | Full outage possible. |
Common questions
Is CVE-2020-1631 being exploited?
Yes. CVE-2020-1631 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2020-1631?
CVE-2020-1631 is rated High with a CVSS score of 8.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2020-1631?
Yes. A fix has been recorded for CVE-2020-1631. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2020-1631 affect?
CVE-2020-1631 affects juniper:junos. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Other links (2)
- kb.juniper.net /JSA11021
- cisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2020-1631
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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