CVE-2026-20280
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conduct
CVSS
8.8
High
EPSS
—
KEV
—
Exploit Today
0
0-100
Published: Sep 2, 2026 · Last modified: Sep 3, 2026 · CWE-703
Not enough EPSS history yet.
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20280 are related to improper checking or handling of exceptional condition issues that are grouped under the Common Weakness Enumeration (CWE) CWE-703.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-57445——
———Gardens v2 is a modular governance framework that enables communities to create and manage multiple governance pools with customizable parameters and voting mechanisms. In dfba919e218e20d52db9f7b2e8d292d45a46c91b and prior, normal beneficiary payout paths in StreamingEscrow preserve depositAmount() while an active stream needs an escrow reserve. However, the approve-side dispute resolution path drains the whole available escrow balance to the proposal beneficiary. At time of publication, there are no publicly known patches.18hCVE-2026-824175.3 MED17.6%
——5### Summary
`qs.stringify` throws a `TypeError` when it serializes an object whose own `constructor` property has a truthy, non-callable `isBuffer` member. `utils.isBuffer` duck-types buffers by calling `obj.constructor.isBuffer(obj)` after checking only that the property is truthy, so a value such as `{ constructor: { isBuffer: "x" } }` makes the call throw `TypeError: obj.constructor.isBuffer is not a function`.
### Details
`lib/stringify.js:127` calls `utils.isBuffer` on every non-primitive value it serializes. `utils.isBuffer` (`lib/utils.js:332`) reads `obj.constructor.isBuffer` and invokes it without verifying that it is a function. `constructor` and `isBuffer` are ordinary property names, so any object carrying them as own properties reaches the unchecked call.
Such an object can be built from untrusted input. `qs.parse("x[constructor][isBuffer]=y", { plainObjects: true })` or `{ allowPrototypes: true }` keeps the `constructor` key as an own property (the default parse options drop it), and `JSON.parse("{\"a\":{\"constructor\":{\"isBuffer\":\"x\"}}}")` produces the same shape with no qs option involved. Express 4 with its default `query parser` setting and body-parser with `extended: true` both call `qs.parse` with `allowPrototypes: true`, so on those stacks `req.query` and `req.body` can carry the shape directly.
#### PoC
```js
var qs = require("qs");
qs.stringify(qs.parse("x[constructor][isBuffer]=y", { plainObjects: true }));
qs.stringify(JSON.parse("{\"a\":{\"constructor\":{\"isBuffer\":\"x\"}}}"));
// TypeError: obj.constructor.isBuffer is not a function
// at Object.isBuffer (lib/utils.js:332:78)
// at stringify (lib/stringify.js:127:45)
```
#### Fix
`lib/utils.js`, applied in e83d321 on `main` and released as v6.16.0:
```diff
- return !!(obj.constructor && obj.constructor.isBuffer && obj.constructor.isBuffer(obj));
+ return !!(obj.constructor && typeof obj.constructor.isBuffer === "function" && obj.constructor.isBuffer(obj));
```
Real `Buffer`, `safer-buffer`, and browserify `buffer` polyfill instances serialize exactly as before; only the throw is removed.
### Affected versions
`>=2.2.5 <6.16.0`, fixed in v6.16.0.
The unguarded duck-type was introduced in 3768a75 and first shipped in v2.2.5 (September 2014). v2.2.4 and earlier used `Buffer.isBuffer` and are not affected. Every release from v2.2.5 through v6.15.3 contains the unguarded call.
### Impact
An unauthenticated request can make any code path that re-serializes attacker-influenced data with `qs.stringify` (for example, rebuilding a query string from `req.query` for a redirect or an upstream request, or serializing a parsed JSON body) throw synchronously. In a typical Node.js HTTP framework the throw is caught by the framework error boundary and the affected request returns a 500; the process survives and other requests are unaffected. Where the call runs outside an error boundary, such as an `async` Express 4 handler (where the throw becomes an unhandled promise rejection) or a background job, the process exits, so the impact in that case depends on the application error handling rather than on qs.18hCVE-2026-264467.5 HIG27.1%
——8Stomper 5e2741e is vulnerable to Denial of Service. When a broker sends data to a client whose TCP connection was already closed by the peer, the server process receives SIGPIPE and immediately terminates, resulting in a denial of service. Any unauthenticated client can trigger the crash by closing the socket at specific points.7dCVE-2026-653514.3 MED38.1%
——11This issue was addressed through improved state management. This issue is fixed in Safari 26.6.1, iOS 26.6.1 and iPadOS 26.6.1, macOS Tahoe 26.6.2. Processing maliciously crafted web content may lead to an unexpected Safari crash.16dCVE-2026-653404.3 MED39.1%
——12This issue was addressed through improved state management. This issue is fixed in Safari 26.6.1, iOS 18.7.10 and iPadOS 18.7.10, iOS 26.6.1 and iPadOS 26.6.1, macOS Tahoe 26.6.2. Processing maliciously crafted web content may lead to an unexpected Safari crash.17dCVE-2026-653374.3 MED39.1%
——12This issue was addressed through improved state management. This issue is fixed in Safari 26.6.1, iOS 18.7.10 and iPadOS 18.7.10, iOS 26.6.1 and iPadOS 26.6.1, macOS Tahoe 26.6.2. Processing maliciously crafted web content may lead to an unexpected Safari crash.17d