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CVE-2019-15802· NVD / CVE Program· CNA mitre

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.

An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0. The firmware hashes and encrypts passwords using a hardcoded cryptographic key in sal_util_str_encrypt() in libsal.so.0.0. The parameters (salt, IV, and key data) are used to encrypt and decrypt all passwords using AES256 in CBC mode. With the parameters known, all previously encrypted passwords can be decrypted. This includes the passwords that are part of configuration backups or otherwise embedded as part of the firmware.

MediumCVSS 5.9 · v3.1—No exploit No fix recorded
Published
Nov 14, 2019
Updated
Jun 16, 2026
EPSS
1.5% · 73th percentile
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Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 1.5%

Noroxi analysis

No Noroxi analysis for this record yet

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Affected systems

VendorProduct
zyxelgs1900-8 firmware
zyxelgs1900-8
zyxelgs1900-8hp firmware
zyxelgs1900-8hp
zyxelgs1900-10hp firmware
zyxelgs1900-10hp
zyxelgs1900-16 firmware
zyxelgs1900-16
zyxelgs1900-24e firmware
zyxelgs1900-24e
zyxelgs1900-24 firmware
zyxelgs1900-24

and 6 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zyxel gs1900-10hp firmwarebefore 2.50\(aazi.0\)c0
  • zyxel gs1900-16 firmwarebefore 2.50\(aahj.0\)c0
  • zyxel gs1900-24 firmwarebefore 2.50\(aahl.0\)c0
  • zyxel gs1900-24e firmwarebefore 2.50\(aahk.0\)c0
  • zyxel gs1900-24hp firmwarebefore 2.50\(aahm.0\)c0
  • zyxel gs1900-48 firmwarebefore 2.50\(aahn.0\)c0
  • zyxel gs1900-48hp firmwarebefore 2.50\(aaho.0\)c0
  • zyxel gs1900-8 firmwarebefore 2.50\(aahh.0\)c0
  • zyxel gs1900-8hp firmwarebefore 2.50\(aahi.0\)c0

Same product

zyxel: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-7273A stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow aKEV
    66This week
  • CVE-2019-15800An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    40Plan
  • CVE-2019-15803An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    36Monitor
  • CVE-2019-15799An issue was discovered on Zyxel GS1900 devices with firmware before 2.50(AAHH.0)C0.
    36Monitor
  • CVE-2021-35031A vulnerability in the TFTP client of Zyxel GS1900 series firmware, XGS1210 series firmware, and XGS1250 series firmware, which could allow
    32Monitor
  • CVE-2021-35032A vulnerability in the 'libsal.so' of the Zyxel GS1900 series firmware version 2.60 could allow an authenticated local user to execute arbit
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

EPSS, last 120 days

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 researchers

Finders, 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.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
high · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-798 · Use of Hard-coded Credentials

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

nvd-primary

Root cause

For convenience in support or manufacturing, an account that is identical on every device is embedded in the software. Credentials learned from one device work on all of them.

The bug in code

The whole CWE-798 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const SUPPORT_USER = "support";const SUPPORT_PASS = "hardcoded-password";

Fixed

ts
const creds = await provisioning.deviceCredentials(deviceId);if (creds.mustRotate) await forcePasswordChange(deviceId);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records