### Description In `symfony/ux-live-component`, a component's server-side state is exposed to the browser as a set of props (`#[LiveProp]`-annotated properties). Props marked `writable: true` can be freely changed by the client. Read-only props are round-tripped to the browser and back, and their integrity is protected by an HMAC so the client cannot tamper with them. Child components additionally receive a `propsFromParent` blob, also HMAC-signed. The HMAC computed by `Symfony\UX\LiveComponent\LiveComponentHydrator` covered only the sorted prop key/value pairs. It didn't include the component name, the slot identifier (`props` vs `propsFromParent`), or any request context, and a single application-wide secret is used for every component. A signed blob the server minted for component A is therefore a valid signature for component B if the key names happen to match, and a `props` blob can be replayed in the `propsFromParent` slot (or the reverse). An attacker can use this to set a read-only prop on a target component to a value they were only ever allowed to choose as a writable prop on another component. ### Resolution The HMAC is now bound to its context: the component name and a slot identifier are included in the pre-image before hashing. Two constants (`CHECKSUM_SLOT_PROPS` and `CHECKSUM_SLOT_PROPS_FROM_PARENT`) name the two slots, and `calculateChecksum()`, `verifyChecksum()`, `addChecksumToData()`, and `ChildComponentPartialRenderer` thread these values through. Cross-component and cross-slot replays no longer verify. The patch for this issue is available [here](https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c) for branch 2.x (and forward-ported to 3.x). ### Credits Symfony would like to thank Anthropic (via Project Glasswing) for reporting the issue and Hugo Alliaume for providing the fix.
### Description In `symfony/ux-live-component`, a component's server-side state is exposed to the browser as a set of props (`#[LiveProp]`-annotated properties). Props marked `writable: true` can be freely changed by the client. Read-only props are round-tripped to the browser and back, and their integrity is protected by an HMAC so the client cannot tamper with them. Child components additionally receive a `propsFromParent` blob, also HMAC-signed. The HMAC computed by `Symfony\UX\LiveComponent\LiveComponentHydrator` covered only the sorted prop key/value pairs. It didn't include the component name, the slot identifier (`props` vs `propsFromParent`), or any request context, and a single application-wide secret is used for every component. A signed blob the server minted for component A is therefore a valid signature for component B if the key names happen to match, and a `props` blob can be replayed in the `propsFromParent` slot (or the reverse). An attacker can use this to set a read-only prop on a target component to a value they were only ever allowed to choose as a writable prop on another component. ### Resolution The HMAC is now bound to its context: the component name and a slot identifier are included in the pre-image before hashing. Two constants (`CHECKSUM_SLOT_PROPS` and `CHECKSUM_SLOT_PROPS_FROM_PARENT`) name the two slots, and `calculateChecksum()`, `verifyChecksum()`, `addChecksumToData()`, and `ChildComponentPartialRenderer` thread these values through. Cross-component and cross-slot replays no longer verify. The patch for this issue is available [here](https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c) for branch 2.x (and forward-ported to 3.x). ### Credits Symfony would like to thank Anthropic (via Project Glasswing) for reporting the issue and Hugo Alliaume for providing the fix.
Update symfony/ux-live-component to 2.36.0; symfony/ux-live-component to 3.1.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scansymfony/ux-live-component: LiveComponentHydrator HMAC checksum lacks component and slot binding affects symfony/ux-live-component (composer), symfony/ux-live-component (composer). Severity is medium. ### Description In `symfony/ux-live-component`, a component's server-side state is exposed to the browser as a set of props (`#[LiveProp]`-annotated properties). Props marked `writable: true` can be freely changed by the client. Read-only props are round-tripped to the browser and back, and their integrity is protected by an HMAC so the client cannot tamper with them. Child components additionally receive a `propsFromParent` blob, also HMAC-signed. The HMAC computed by `Symfony\UX\LiveComponent\LiveComponentHydrator` covered only the sorted prop key/value pairs. It didn't include the component name, the slot identifier (`props` vs `propsFromParent`), or any request context, and a single application-wide secret is used for every component. A signed blob the server minted for component A is therefore a valid signature for component B if the key names happen to match, and a `props` blob can be replayed in the `propsFromParent` slot (or the reverse). An attacker can use this to set a read-only prop on a target component to a value they were only ever allowed to choose as a writable prop on another component. ### Resolution The HMAC is now bound to its context: the component name and a slot identifier are included in the pre-image before hashing. Two constants (`CHECKSUM_SLOT_PROPS` and `CHECKSUM_SLOT_PROPS_FROM_PARENT`) name the two slots, and `calculateChecksum()`, `verifyChecksum()`, `addChecksumToData()`, and `ChildComponentPartialRenderer` thread these values through. Cross-component and cross-slot replays no longer verify. The patch for this issue is available [here](https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c) for branch 2.x (and forward-ported to 3.x). ### Credits Symfony would like to thank Anthropic (via Project Glasswing) for reporting the issue and Hugo Alliaume for providing the fix.
AI coding agents often install or upgrade packages automatically in composer. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| symfony/ux-live-componentcomposer | >=2.8.0,<2.36.0 | 2.36.0 |
| symfony/ux-live-componentcomposer | >=3.0.0,<3.1.0 | 3.1.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate symfony/ux-live-component to 2.36.0; symfony/ux-live-component to 3.1.0 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scansymfony/ux-live-component: LiveComponentHydrator HMAC checksum lacks component and slot binding affects symfony/ux-live-component (composer), symfony/ux-live-component (composer). Severity is medium. ### Description In `symfony/ux-live-component`, a component's server-side state is exposed to the browser as a set of props (`#[LiveProp]`-annotated properties). Props marked `writable: true` can be freely changed by the client. Read-only props are round-tripped to the browser and back, and their integrity is protected by an HMAC so the client cannot tamper with them. Child components additionally receive a `propsFromParent` blob, also HMAC-signed. The HMAC computed by `Symfony\UX\LiveComponent\LiveComponentHydrator` covered only the sorted prop key/value pairs. It didn't include the component name, the slot identifier (`props` vs `propsFromParent`), or any request context, and a single application-wide secret is used for every component. A signed blob the server minted for component A is therefore a valid signature for component B if the key names happen to match, and a `props` blob can be replayed in the `propsFromParent` slot (or the reverse). An attacker can use this to set a read-only prop on a target component to a value they were only ever allowed to choose as a writable prop on another component. ### Resolution The HMAC is now bound to its context: the component name and a slot identifier are included in the pre-image before hashing. Two constants (`CHECKSUM_SLOT_PROPS` and `CHECKSUM_SLOT_PROPS_FROM_PARENT`) name the two slots, and `calculateChecksum()`, `verifyChecksum()`, `addChecksumToData()`, and `ChildComponentPartialRenderer` thread these values through. Cross-component and cross-slot replays no longer verify. The patch for this issue is available [here](https://github.com/symfony/ux/commit/a224b5af3e2e33ee14ac71356ae0e0877900a81c) for branch 2.x (and forward-ported to 3.x). ### Credits Symfony would like to thank Anthropic (via Project Glasswing) for reporting the issue and Hugo Alliaume for providing the fix.
AI coding agents often install or upgrade packages automatically in composer. A medium vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| symfony/ux-live-componentcomposer | >=2.8.0,<2.36.0 | 2.36.0 |
| symfony/ux-live-componentcomposer | >=3.0.0,<3.1.0 | 3.1.0 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard