Cisco ASA Secondary Authentication Bypass Vulnerability
A vulnerability in the Cisco ASA that could allow a remote attacker to successfully authenticate using the Cisco AnyConnect VPN client if the Secondary Authentication type is LDAP and the password is left blank, providing the primary credentials are correct. The vulnerabilities is due to improper input validation of certain parameters passed to the affected software. An attacker must have the correct primary credentials in order to successfully exploit this vulnerability.
- Published
- Feb 18, 2020
- Updated
- Jun 16, 2026
- EPSS
- 0.9% · 57th percentile
- CWE
- CWE-287
Sign in to follow · You’ll be notified if a followed record enters KEV, gets an exploit or is updated.
Report tools
Action score
30
Monitor
Low priority for now.
- CVSS
- 30 / 40 · 7.5 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.9%
CISA SSVC decision
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- 7.5
- CNA · cisco
- 4.3
- 3.2 point gap
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | asa 5500 firmware | cpe:2.3:o:cisco:asa_5500_firmware |
| cisco | asa 5500 | cpe:2.3:h:cisco:asa_5500 |
| cisco | asa 5510 firmware | cpe:2.3:o:cisco:asa_5510_firmware |
| cisco | asa 5510 | cpe:2.3:h:cisco:asa_5510 |
| cisco | asa 5512-x firmware | cpe:2.3:o:cisco:asa_5512-x_firmware |
| cisco | asa 5512-x | cpe:2.3:h:cisco:asa_5512-x |
| cisco | asa 5515-x firmware | cpe:2.3:o:cisco:asa_5515-x_firmware |
| cisco | asa 5515-x | cpe:2.3:h:cisco:asa_5515-x |
| cisco | asa 5520 firmware | cpe:2.3:o:cisco:asa_5520_firmware |
| cisco | asa 5520 | cpe:2.3:h:cisco:asa_5520 |
| cisco | asa 5525-x firmware | cpe:2.3:o:cisco:asa_5525-x_firmware |
| cisco | asa 5525-x | cpe:2.3:h:cisco:asa_5525-x |
and 12 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco asa 5500 firmware8.4(1)
- cisco asa 5510 firmware8.4(1)
- cisco asa 5512-x firmware8.4(1)
- cisco asa 5515-x firmware8.4(1)
- cisco asa 5520 firmware8.4(1)
- cisco asa 5525-x firmware8.4(1)
- cisco asa 5540 firmware8.4(1)
- cisco asa 5545-x firmware8.4(1)
- cisco asa 5550 firmware8.4(1)
- cisco asa 5555-x firmware8.4(1)
- cisco asa 5580 firmware8.4(1)
- cisco asa 5585-x firmware8.4(1)
Versions reported by the vendor
Affected version ranges reported by the assigning authority (cisco). Independent of NVD's CPE analysis and usually ahead of it.
Cisco Cisco ASA
- 8.4(1)affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| openSUSE:Tumbleweed | libsoup | before 2.56.0-1.1 | 2.56.0-1.1 |
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2019-1649Cisco Secure Boot Hardware Tampering Vulnerability26Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| opensuse:libsoup | 2.56.0-1.1 · openSUSE:Tumbleweed | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- A low-privileged account is enough.
- No user action is required.
- Special conditions such as timing or configuration are required.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-287 · Improper AuthenticationCVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Root cause
Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.
The bug in code
The whole CWE-287 classA representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.
Vulnerable
app.use("/admin", requireSession, adminRouter);
// Route added later skips the middlewareapp.post("/admin-api/config", updateConfig);Fixed
const admin = express.Router();admin.use(requireSession, requireRole("admin"));
admin.post("/config", updateConfig);app.use("/admin", admin);Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Authentication AbuseCAPEC-114Medium
- Authentication BypassCAPEC-115Medium
- Identity SpoofingCAPEC-151likelihood: Medium · Medium
- Fake the Source of DataCAPEC-194Medium
- Exploiting Trust in ClientCAPEC-22likelihood: High · High
- Utilizing REST's Trust in the System Resource to Obtain Sensitive DataCAPEC-57likelihood: Medium · Very High
- Session HijackingCAPEC-593likelihood: High · Very High
- Token ImpersonationCAPEC-633Medium
ATT&CK techniques
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
Vendor advisories and official records. Exploit/PoC links are deliberately left out.